Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Refine search result
123456 1 - 50 of 298
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Agapitov, Oleksiy
    et al.
    Artemyev, Anton
    Krasnoselskikh, Vladimir
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Mourenas, Didier
    Breuillard, Hugo
    Balikhin, Michael
    Rolland, Guy
    Statistics of whistler mode waves in the outer radiation belt: Cluster STAFF-SA measurements2013In: Journal of Geophysical Research-Space Physics, ISSN 2169-9380, Vol. 118, no 6, p. 3407-3420Article in journal (Refereed)
    Abstract [en]

    ELF/VLF waves play a crucial role in the dynamics of the radiation belts and are partly responsible for the main losses and the acceleration of energetic electrons. Modeling wave-particle interactions requires detailed information of wave amplitudes and wave normal distribution over L-shells and over magnetic latitudes for different geomagnetic activity conditions. We performed a statistical study of ELF/VLF emissions using wave measurements in the whistler frequency range for 10years (2001-2010) aboard Cluster spacecraft. We utilized data from the STAFF-SA experiment, which spans the frequency range from 8Hz to 4kHz. We present distributions of wave magnetic and electric field amplitudes and wave normal directions as functions of magnetic latitude, magnetic local time, L-shell, and geomagnetic activity. We show that wave normals are directed approximately along the background magnetic field (with the mean value of the angle between the wave normal and the background magnetic field, about 10 degrees-15 degrees) in the vicinity of the geomagnetic equator. The distribution changes with magnetic latitude: Plasmaspheric hiss normal angles increase with latitude to quasi-perpendicular direction at approximate to 35 degrees-40 degrees where hiss can be reflected; lower band chorus are observed as two wave populations: One population of wave normals tends toward the resonance cone and at latitudes of around 35 degrees-45 degrees wave normals become nearly perpendicular to the magnetic field; the other part remains quasi-parallel at latitudes up to 30 degrees. The observed angular distribution is significantly different from Gaussian, and the width of the distribution increases with latitude. Due to the rapid increase of , the wave mode becomes quasi-electrostatic, and the corresponding electric field increases with latitude and has a maximum near 30 degrees. The magnetic field amplitude of the chorus in the day sector has a minimum at the magnetic equator but increases rapidly with latitude with a local maximum near 12 degrees-15 degrees. The wave magnetic field maximum is observed in the night sector at L>7 during low geomagnetic activity (at L approximate to 5 for K-p>3). Our results confirm the strong dependence of wave amplitude on geomagnetic activity found in earlier studies.

  • 2. Agapitov, Oleksiy
    et al.
    Krasnoselskikh, Vladimir
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Rolland, Guy
    A statistical study of the propagation characteristics of whistler waves observed by Cluster2011In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 38, p. L20103-Article in journal (Refereed)
    Abstract [en]

    VLF waves play a crucial role in the dynamics of radiation belts, and are responsible for the loss and the acceleration of energetic electrons. Modeling wave-particle interactions requires the best possible knowledge for how wave energy and wave-normal directions are distributed in L-shells and for the magnetic latitudes of different magnetic activity conditions. In this work, we performed a statistical study for VLF emissions using a whistler frequency range for nine years (2001-2009) of Cluster measurements. We utilized data from the STAFF-SA experiment, which spans the frequency range from 8.8 Hz to 3.56 kHz. We show that the wave energy distribution has two maxima around L similar to 4.5 = 6 and L similar to 2, and that wave-normals are directed approximately along the magnetic field in the vicinity of the geomagnetic equator. The distribution changes with magnetic latitude, and so that at latitudes of similar to 30 degrees, wave-normals become nearly perpendicular to the magnetic field. The observed angular distribution is significantly different from Gaussian and the width of the distribution increases with latitude. Since the resonance condition for wave-particle interactions depends on the wave normal orientation, our results indicate that, due to the observed change in the wave-normal direction with latitude, the most efficient particle diffusion due to wave-particle interaction should occur in a limited region surrounding the geomagnetic equator.

  • 3.
    Alho, M.
    et al.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Battarbee, M.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Pfau-Kempf, Y.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, Linz, Austria..
    Cozzani, G.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Ganse, U.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Turc, L.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Johlander, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Univ Helsinki, Dept Phys, Helsinki, Finland..
    Horaites, K.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Tarvus, V
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Zhou, H.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Grandin, M.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Dubart, M.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Papadakis, K.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Suni, J.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    George, H.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Bussov, M.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Palmroth, M.
    Univ Helsinki, Dept Phys, Helsinki, Finland.;Finnish Meteorol Inst, Helsinki, Finland..
    Electron Signatures of Reconnection in a Global eVlasiator Simulation2022In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 49, no 14, article id e2022GL098329Article in journal (Refereed)
    Abstract [en]

    Geospace plasma simulations have progressed toward more realistic descriptions of the solar wind-magnetosphere interaction from magnetohydrodynamic to hybrid ion-kinetic, such as the state-of-the-art Vlasiator model. Despite computational advances, electron scales have been out of reach in a global setting. eVlasiator, a novel Vlasiator submodule, shows for the first time how electromagnetic fields driven by global hybrid-ion kinetics influence electrons, resulting in kinetic signatures. We analyze simulated electron distributions associated with reconnection sites and compare them with Magnetospheric Multiscale (MMS) spacecraft observations. Comparison with MMS shows that key electron features, such as reconnection inflows, heated outflows, flat-top distributions, and bidirectional streaming, are in remarkable agreement. Thus, we show that many reconnection-related features can be reproduced despite strongly truncated electron physics and an ion-scale spatial resolution. Ion-scale dynamics and ion-driven magnetic fields are shown to be significantly responsible for the environment that produces electron dynamics observed by spacecraft in near-Earth plasmas.

    Download full text (pdf)
    fulltext
  • 4.
    Allen, R. C.
    et al.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Cernuda, I
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Pacheco, D.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Berger, L.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Xu, Z. G.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    von Forstner, J. L. Freiherr
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Rodriguez-Pacheco, J.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Wimmer-Schweingruber, R. F.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Ho, G. C.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Mason, G. M.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Vines, S. K.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Horbury, T.
    Imperial Coll, London, England..
    Maksimovic, M.
    Univ Paris Diderot, Observ Paris, Sorbonne Univ, CNRS,LESIA,Univ PSL, Sorbonne Paris Cite,5 Pl Jules Janssen, F-92195 Meudon, France..
    Hadid, L. Z.
    Univ Paris Saclay, Observ Paris, Sorbonne Univ, Ecole Polytech,CNRS,LPP, Paris, France..
    Volwerk, M.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Dimmock, Andrew P.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Sorriso-Valvo, Luca
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. CNR ISTP Ist Sci & Tecnol Plasmi, Via Amendola 122-D, I-70126 Bari, Italy..
    Stergiopoulou, Katerina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Andrews, G. B.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Angelini, V
    Imperial Coll, London, England..
    Bale, S. D.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.;Univ Calif Berkeley, Phys Dept, Berkeley, CA 94720 USA..
    Boden, S.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany.;DSI Datensicherheit GmbH, Rodendamm 34, D-28816 Stuhr, Germany..
    Boettcher, S. , I
    Chust, T.
    Univ Paris Saclay, Observ Paris, Sorbonne Univ, Ecole Polytech,CNRS,LPP, Paris, France..
    Eldrum, S.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Espada, P. P.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Lara, F. Espinosa
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Evans, V
    Imperial Coll, London, England..
    Gomez-Herrero, R.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Hayes, J. R.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Hellin, A. M.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Kollhoff, A.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Krasnoselskikh, V
    CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France..
    Kretzschmar, M.
    CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France.;Univ Orleans, Orleans, France..
    Kuehl, P.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Kulkarni, S. R.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany.;Deutsch Elektronen Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Lees, W. J.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Lorfevre, E.
    CNES, Toulouse, France..
    Martin, C.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany.;German Aerosp Ctr, Dept Extrasolar Planets & Atmospheres, Berlin, Germany..
    O'Brien, H.
    Imperial Coll, London, England..
    Plettemeier, D.
    Tech Univ Dresden, Dresden, Germany..
    Polo, O. R.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Prieto, M.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Ravanbakhsh, A.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany.;Max Planck Inst Solar Syst Res, Gottingen, Germany..
    Sanchez-Prieto, S.
    Univ Alcala De Henares, Space Res Grp, Madrid, Spain..
    Schlemm, C. E.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Seifert, H.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA..
    Soucek, J.
    Czech Acad Sci, Inst Atmospher Phys, Prague, Czech Republic..
    Steller, M.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Stverak, S.
    Czech Acad Sci, Astron Inst, Prague, Czech Republic..
    Terasa, J. C.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany..
    Travnicek, P.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.;Czech Acad Sci, Astron Inst, Prague, Czech Republic..
    Tyagi, K.
    Johns Hopkins Appl Phys Lab, Laurel, MD 20723 USA.;Univ Colorado, LASP, Boulder, CO 80309 USA..
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Space & Plasma Phys, Stockholm, Sweden..
    Vecchio, A.
    Univ Paris Diderot, Observ Paris, Sorbonne Univ, CNRS,LESIA,Univ PSL, Sorbonne Paris Cite,5 Pl Jules Janssen, F-92195 Meudon, France.;Radboud Univ Nijmegen, Res Inst Math Astrophys & Particle Phys, Nijmegen, Netherlands..
    Yedla, M.
    Christian Albrechts Univ Kiel, Inst Expt & Angewande Phys, D-24118 Kiel, Germany.;Max Planck Inst Solar Syst Res, Gottingen, Germany..
    Energetic ions in the Venusian system: Insights from the first Solar Orbiter flyby2021In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 656, article id A7Article in journal (Refereed)
    Abstract [en]

    The Solar Orbiter flyby of Venus on 27 December 2020 allowed for an opportunity to measure the suprathermal to energetic ions in the Venusian system over a large range of radial distances to better understand the acceleration processes within the system and provide a characterization of galactic cosmic rays near the planet. Bursty suprathermal ion enhancements (up to similar to 10 keV) were observed as far as similar to 50R(V) downtail. These enhancements are likely related to a combination of acceleration mechanisms in regions of strong turbulence, current sheet crossings, and boundary layer crossings, with a possible instance of ion heating due to ion cyclotron waves within the Venusian tail. Upstream of the planet, suprathermal ions are observed that might be related to pick-up acceleration of photoionized exospheric populations as far as 5R(V) upstream in the solar wind as has been observed before by missions such as Pioneer Venus Orbiter and Venus Express. Near the closest approach of Solar Orbiter, the Galactic cosmic ray (GCR) count rate was observed to decrease by approximately 5 percent, which is consistent with the amount of sky obscured by the planet, suggesting a negligible abundance of GCR albedo particles at over 2 R-V. Along with modulation of the GCR population very close to Venus, the Solar Orbiter observations show that the Venusian system, even far from the planet, can be an effective accelerator of ions up to similar to 30 keV. This paper is part of a series of the first papers from the Solar Orbiter Venus flyby.

    Download full text (pdf)
    FULLTEXT01
  • 5.
    Alm, L.
    et al.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Argall, M. R.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Torbert, R. B.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA.;Southwest Res Inst, San Antonio, TX USA..
    Farrugia, C. J.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA..
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA..
    Russell, C. T.
    Univ Calif Los Angeles, IGPP EPSS, Los Angeles, CA USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, IGPP EPSS, Los Angeles, CA USA..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Marklund, G. T.
    KTH Royal Inst Technol, Stockholm, Sweden..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Shuster, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.;Univ Maryland, Coll Comp Math & Nat Sci, College Pk, MD 20742 USA..
    EDR signatures observed by MMS in the 16 October event presented in a 2-D parametric space2017In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 3, p. 3262-3276Article in journal (Refereed)
    Abstract [en]

    We present a method for mapping the position of satellites relative to the X line using the measured B-L and B-N components of the magnetic field and apply it to the Magnetospheric multiscale (MMS) encounter with the electron diffusion region (EDR) which occurred on 13:07 UT on 16 October 2015. Mapping the data to our parametric space succeeds in capturing many of the signatures associated with magnetic reconnection and the electron diffusion region. This offers a method for determining where in the reconnection region the satellites were located. In addition, parametric mapping can also be used to present data from numerical simulations. This facilitates comparing data from simulations with data from in situ observations as one can avoid the complicated process using boundary motion analysis to determine the geometry of the reconnection region. In parametric space we can identify the EDR based on the collocation of several reconnection signatures, such as electron nongyrotropy, electron demagnetization, parallel electric fields, and energy dissipation. The EDR extends 2-3km in the normal direction and in excess of 20km in the tangential direction. It is clear that the EDR occurs on the magnetospheric side of the topological X line, which is expected in asymmetric reconnection. Furthermore, we can observe a north-south asymmetry, where the EDR occurs north of the peak in out-of-plane current, which may be due to the small but finite guide field.

  • 6.
    Alm, L.
    et al.
    Univ New Hampshire, Space Sci Ctr, Durham, NH, USA.
    Farrugia, C. J.
    Univ New Hampshire, Space Sci Ctr, Durham, NH USA.
    Paulson, K. W.
    Univ New Hampshire, Space Sci Ctr, Durham, NH USA.
    Argall, M. R.
    Univ New Hampshire, Space Sci Ctr, Durham, NH USA.
    Torbert, R. B.
    Univ New Hampshire, Space Sci Ctr, Durham, NH USA; Southwest Res Inst, San Antonio, TX USA.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO USA.
    Russell, C. T.
    Univ Calif Los Angeles, IGPP EPSS, Los Angeles, CA USA.
    Strangeway, R. J.
    Univ Calif Los Angeles, IGPP EPSS, Los Angeles, CA USA.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    KTH Royal Inst Technol, Dept Space & Plasma Phys, Stockholm, Sweden.
    Marklund, G. T.
    KTH Royal Inst Technol, Dept Space & Plasma Phys, Stockholm, Sweden.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Differing Properties of Two Ion-Scale Magnetopause Flux Ropes2018In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 1, p. 114-131Article in journal (Refereed)
    Abstract [en]

    In this paper, we present results from the Magnetospheric Multiscale constellation encountering two ion‐scale, magnetopause flux ropes. The two flux ropes exhibit very different properties and internal structure. In the first flux rope, there are large differences in the currents observed by different satellites, indicating variations occurring over sub‐di spatial scales, and time scales on the order of the ion gyroperiod. In addition, there is intense wave activity and particle energization. The interface between the two flux ropes exhibits oblique whistler wave activity. In contrast, the second flux rope is mostly quiescent, exhibiting little activity throughout the encounter. Changes in the magnetic topology and field line connectivity suggest that we are observing flux rope coalescence.

    Download full text (pdf)
    fulltext
  • 7.
    Alm, Love
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    KTH Royal Inst Technol, Stockholm, Sweden.
    Chappell, Charles R.
    Vanderbilt Univ, Dept Phys & Astron, Vanderbilt Dyer Observ, Nashville, TN 37235 USA.
    Dargent, Jeremy
    Univ Pisa, Phys Dept Enrico Fermi, Pisa, Italy.
    Fuselier, Stephen A.
    Southwest Res Inst, San Antonio, TX USA;Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX USA.
    Haaland, Stein
    Max Planck Inst Solar Syst Res, Gottingen, Germany;Univ Bergen, Birkeland Ctr Space Sci, Bergen, Norway.
    Lavraud, Benoit
    Univ Toulouse, Inst Rech Astrophys & Planetol, CNRS, UPS,CNES, Toulouse, France.
    Li, Wenya
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China.
    Tenfjord, Paul
    Univ Bergen, Birkeland Ctr Space Sci, Bergen, Norway.
    Toledo-Redondo, Sergio
    Univ Toulouse, Inst Rech Astrophys & Planetol, CNRS, UPS,CNES, Toulouse, France.
    Vines, Sarah K.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA.
    MMS Observations of Multiscale Hall Physics in the Magnetotail2019In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 46, no 17-18, p. 10230-10239Article in journal (Refereed)
    Abstract [en]

    We present Magnetospheric Multiscale mission (MMS) observations of Hall physics in the magnetotail, which compared to dayside Hall physics is a relatively unexplored topic. The plasma consists of electrons, moderately cold ions (T similar to 1.5 keV) and hot ions (T similar to 20 keV). MMS can differentiate between the cold ion demagnetization region and hot ion demagnetization regions, which suggests that MMS was observing multiscale Hall physics. The observed Hall electric field is compared with a generalized Ohm's law, accounting for multiple ion populations. The cold ion population, despite its relatively high initial temperature, has a significant impact on the Hall electric field. These results show that multiscale Hall physics is relevant over a much larger temperature range than previously observed and is relevant for the whole magnetosphere as well as for other astrophysical plasma.

  • 8.
    Alm, Love
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Torbert, R. B.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA;Southwest Res Inst, San Antonio, TX USA.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.
    Ergun, R. E.
    Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA.
    Lindqvist, P. -A
    Russell, C. T.
    Univ Calif Los Angeles, IGPP EPSS, Los Angeles, CA USA.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Mauk, B. H.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA.
    Magnetotail Hall Physics in the Presence of Cold Ions2018In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, no 20, p. 10941-10950Article in journal (Refereed)
    Abstract [en]

    We present the first in situ observation of cold ionospheric ions modifying the Hall physics of magnetotail reconnection. While in the tail lobe, Magnetospheric Multiscale mission observed cold (tens of eV) E x B drifting ions. As Magnetospheric Multiscale mission crossed the separatrix of a reconnection exhaust, both cold lobe ions and hot (keV) ions were observed. During the closest approach of the neutral sheet, the cold ions accounted for similar to 30% of the total ion density. Approximately 65% of the initial cold ions remained cold enough to stay magnetized. The Hall electric field was mainly supported by the j x B term of the generalized Ohm's law, with significant contributions from the del center dot P-e and v(c) x B terms. The results show that cold ions can play an important role in modifying the Hall physics of magnetic reconnection even well inside the plasma sheet. This indicates that modeling magnetic reconnection may benefit from including multiscale Hall physics. Plain Language Summary Cold ions have the potential of changing the fundamental physics behind magnetic reconnection. Here we present the first direct observation of this process in action in the magnetotail. Cold ions from the tail lobes were able to remain cold even deep inside the much hotter plasma sheet. Even though the cold ions only accounted for similar to 30% of the total ions, they had a significant impact on the electric fields near the reconnection region.

  • 9.
    Alqeeq, S. W.
    et al.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Le Contel, O.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Canu, P.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Retino, A.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Chust, T.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Mirioni, L.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Chuvatin, A.
    Univ Paris Saclay, Inst Polytech Paris, UMR7648, Lab Phys Plasmas LPP,CNRS,Sorbonne Univ,Observ Par, Paris, France..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Ahmadi, N.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO USA..
    Wilder, F. D.
    Univ Texas Arlington, Dept Phys, Arlington, TX USA..
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.;Univ Texas San Antonio, San Antonio, TX USA..
    Torbert, R. B.
    Univ New Hampshire, Space Sci Ctr, Durham, NH USA.;Univ New Hampshire, Dept Phys, Durham, NH USA..
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX USA.;Univ Texas San Antonio, San Antonio, TX USA..
    Russell, C. T.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Wei, H. Y.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Bromund, K. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Fischer, D.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Saito, Y.
    Inst Space & Astronaut Sci, Sagamihara, Japan..
    Two Classes of Equatorial Magnetotail Dipolarization Fronts Observed by Magnetospheric Multiscale Mission: A Statistical Overview2023In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 128, no 10, article id e2023JA031738Article in journal (Refereed)
    Abstract [en]

    We carried out a statistical study of equatorial dipolarization fronts (DFs) detected by the Magnetospheric Multiscale mission during the full 2017 Earth's magnetotail season. We found that two DF classes are distinguished: class I (74.4%) corresponds to the standard DF properties and energy dissipation and a new class II (25.6%). This new class includes the six DF discussed in Alqeeq et al. (2022, ) and corresponds to a bump of the magnetic field associated with a minimum in the ion and electron pressures and a reversal of the energy conversion process. The possible origin of this second class is discussed. Both DF classes show that the energy conversion process in the spacecraft frame is driven by the diamagnetic current dominated by the ion pressure gradient. In the fluid frame, it is driven by the electron pressure gradient. In addition, we have shown that the energy conversion processes are not homogeneous at the electron scale mostly due to the variations of the electric fields for both DF classes.

  • 10.
    Alqeeq, S. W.
    et al.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Le Contel, O.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Canu, P.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Retino, A.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Chust, T.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Mirioni, L.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Richard, Louis
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Ait-Si-Ahmed, Y.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Alexandrova, A.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Chuvatin, A.
    Univ Paris Saclay, Inst Polytech Paris, Lab Phys Plasmas LPP,CNRS, Sorbonne Univ,Ecole Polytech,Observ Paris,UMR7648, F-75005 Paris, France..
    Ahmadi, N.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80303 USA..
    Baraka, S. M.
    Hampton Univ, NIA, Hampton, VA 23666 USA..
    Nakamura, R.
    Wilder, F. D.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria.;Univ Texas Arlington, Phys Fac, Arlington, TX 76019 USA..
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Lindqvist, P. A.
    Royal Inst Technol, S-11428 Stockholm, Sweden..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80303 USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Torbert, R. B.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA 90095 USA..
    Magnes, W.
    Hampton Univ, NIA, Hampton, VA 23666 USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA 90095 USA..
    Bromund, K. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Wei, H.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Plaschke, F.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria..
    Anderson, B. J.
    Johns Hopkins Univ, Appl Phys Lab, Johns Hopkins Rd, Laurel, MD 20723 USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Saito, Y.
    Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2525210, Japan..
    Lavraud, B.
    Univ Paul Sabatier, CNRS, UMR5277, Inst Rech Astrophys & Planetol IRAP, F-31400 Toulouse, France..
    Investigation of the homogeneity of energy conversion processes at dipolarization fronts from MMS measurements2022In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 29, no 1, article id 012906Article in journal (Refereed)
    Abstract [en]

    We report on six dipolarization fronts (DFs) embedded in fast earthward flows detected by the Magnetospheric Multiscale mission during a substorm event on 23 July 2017. We analyzed Ohm's law for each event and found that ions are mostly decoupled from the magnetic field by Hall fields. However, the electron pressure gradient term is also contributing to the ion decoupling and likely responsible for an electron decoupling at DF. We also analyzed the energy conversion process and found that the energy in the spacecraft frame is transferred from the electromagnetic field to the plasma (J & BULL; E > 0) ahead or at the DF, whereas it is the opposite (J & BULL; E < 0) behind the front. This reversal is mainly due to a local reversal of the cross-tail current indicating a substructure of the DF. In the fluid frame, we found that the energy is mostly transferred from the plasma to the electromagnetic field (J & BULL; E & PRIME; < 0) and should contribute to the deceleration of the fast flow. However, we show that the energy conversion process is not homogeneous at the electron scales due to electric field fluctuations likely related to lower-hybrid drift waves. Our results suggest that the role of DF in the global energy cycle of the magnetosphere still deserves more investigation. In particular, statistical studies on DF are required to be carried out with caution due to these electron scale substructures.

  • 11.
    Andriopoulou, M.
    et al.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Torkar, K.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Baumjohann, W.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Torbert, R. B.
    Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA..
    Lindqvist, P. -A
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Burch, J. L.
    SW Res Inst, San Antonio, TX USA..
    Russell, C. T.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Study of the spacecraft potential under active control and plasma density estimates during the MMS commissioning phase2016In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 10, p. 4858-4864Article in journal (Refereed)
    Abstract [en]

    Each spacecraft of the recently launched magnetospheric multiscale MMS mission is equipped with Active Spacecraft Potential Control (ASPOC) instruments, which control the spacecraft potential in order to reduce spacecraft charging effects. ASPOC typically reduces the spacecraft potential to a few volts. On several occasions during the commissioning phase of the mission, the ASPOC instruments were operating only on one spacecraft at a time. Taking advantage of such intervals, we derive photoelectron curves and also perform reconstructions of the uncontrolled spacecraft potential for the spacecraft with active control and estimate the electron plasma density during those periods. We also establish the criteria under which our methods can be applied.

  • 12.
    Andriopoulou, Maria
    et al.
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Nakamura, Rumi
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Wellenzohn, Simon
    Karl Franzens Univ Graz, Inst Geophys Astrophys & Meteorol, Graz, Austria.
    Torkar, Klaus
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Baumjohann, Wolfgang
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Torbert, R. B.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA;Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.
    Lindqvist, Per-Arne
    KTH Royal Inst Technol, Dept Space & Plasma Phys, Stockholm, Sweden.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Dorelli, John
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Burch, James L.
    Southwest Res Inst, San Antonio, TX USA.
    Plasma Density Estimates From Spacecraft Potential Using MMS Observations in the Dayside Magnetosphere2018In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 4, p. 2620-2629Article in journal (Refereed)
    Abstract [en]

    Using spacecraft potential observations with and without active spacecraft potential control (on/off) from the Magnetospheric Multiscale (MMS) mission, we estimate the average photoelectron emission as well as derive the plasma density information from spacecraft potential variations and active spacecraft potential control ion current. Such estimates are of particular importance especially during periods when the plasma instruments are not in operation and also when electron density observations with higher time resolution than the ones available from particle detectors are necessary. We compare the average photoelectron emission of different spacecraft and discuss their differences. We examine several time intervals when we performed our density estimations in order to understand the strengths and weaknesses of our data set. We finally compare our derived density estimates with the plasma density observations provided by plasma detectors onboard MMS, whenever available, and discuss the overall results. The estimated electron densities should only be used as a proxy of the electron density, complimentary to the plasma moments derived by plasma detectors, especially when the latter are turned off or when higher time resolution observations are required. While the derived data set can often provide valuable information about the plasma environment, the actual values may often be very far from the actual plasma density values and should therefore be used with caution.

  • 13.
    André, Mats
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Eriksson, Anders, I
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Toledo-Redondo, Sergio
    Univ Murcia, Dept Electromagnetism & Elect, Murcia, Spain..
    The Spacecraft Wake: Interference With Electric Field Observations and a Possibility to Detect Cold Ions2021In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 126, no 9, article id e2021JA029493Article in journal (Refereed)
    Abstract [en]

    Wakes behind spacecraft caused by supersonic drifting positive ions are common in plasmas and disturb in situ measurements. We review the impact of wakes on observations by the Electric Field and Wave double-probe instruments on the Cluster satellites. In the solar wind, the equivalent spacecraft charging is small compared to the ion drift energy and the wake effects are caused by the spacecraft body and can be compensated for. We present statistics of the direction, width, and electrostatic potential of wakes, and we compare with an analytical model. In the low-density magnetospheric lobes, the equivalent positive spacecraft charging is large compared to the ion drift energy and an enhanced wake forms. In this case observations of the geophysical electric field with the double-probe technique becomes extremely challenging. Rather, the wake can be used to estimate the flux of cold (eV) positive ions. For an intermediate range of parameters, when the equivalent charging of the spacecraft is similar to the drift energy of the ions, also the charged wire booms of a double-probe instrument must be taken into account. We discuss an example of these effects from the MMS spacecraft near the magnetopause. We find that many observed wake characteristics provide information that can be used for scientific studies. An important example is the enhanced wakes used to estimate the outflow of ionospheric origin in the magnetospheric lobes to about 10 26 cold (eV) ions/s, constituting a large fraction of the mass outflow from planet Earth.

  • 14.
    Aran, A.
    et al.
    Univ Barcelona UB IEEC, Inst Ciencies Cosmos ICCUB, Dept Fis Quant & Astrofis, Barcelona, Spain..
    Pacheco, D.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Laurenza, M.
    INAF Ist Astrofis & Planetol Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome, Italy..
    Wijsen, N.
    Katholieke Univ Leuven, Ctr Math Plasma Astrophys, Dept Math, Celestijnenlaan 200B, B-3001 Leuven, Belgium..
    Lario, D.
    NASA Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA..
    Benella, S.
    INAF Ist Astrofis & Planetol Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome, Italy..
    Richardson, I. G.
    NASA Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Samara, E.
    Katholieke Univ Leuven, Ctr Math Plasma Astrophys, Dept Math, Celestijnenlaan 200B, B-3001 Leuven, Belgium.;Royal Observ Belgium, Solar Terr Ctr Excellence SIDC, B-1180 Brussels, Belgium..
    von Forstner, J. L. Freiherr
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany.;Paradox Cat GmbH, D-80333 Munich, Germany..
    Sanahuja, B.
    Univ Barcelona UB IEEC, Inst Ciencies Cosmos ICCUB, Dept Fis Quant & Astrofis, Barcelona, Spain..
    Rodriguez, L.
    Royal Observ Belgium, Solar Terr Ctr Excellence SIDC, B-1180 Brussels, Belgium..
    Balmaceda, L.
    NASA Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA.;George Mason Univ, Fairfax, VA 22030 USA..
    Lara, F. Espinosa
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Gomez-Herrero, R.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Steinvall, Konrad
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics.
    Vecchio, A.
    Univ Paris, LESIA, Observ Paris, Univ PSL,CNRS,Sorbonne Univ, 5 Pl Jules Janssen, F-92195 Meudon, France.;Radboud Univ Nijmegen, Dept Astrophys, Radboud Radio Lab, Nijmegen, Netherlands..
    Krupar, V
    NASA Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA.;Univ Maryland Baltimore Cty, Goddard Planetary Heliophys Inst, Baltimore, MD 21228 USA..
    Poedts, S.
    Katholieke Univ Leuven, Ctr Math Plasma Astrophys, Dept Math, Celestijnenlaan 200B, B-3001 Leuven, Belgium.;Univ Maria Curie Sklodowska, Inst Phys, Ul Radziszewskiego 10, PL-20031 Lublin, Poland..
    Allen, R. C.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Andrews, G. B.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Angelini, V
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Berger, L.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Berghmans, D.
    Royal Observ Belgium, Solar Terr Ctr Excellence SIDC, B-1180 Brussels, Belgium..
    Boden, S.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany.;DSI Datensicherheit GmbH, Rodendamm 34, D-28816 Stuhr, Germany..
    Bottcher, S. , I
    Carcaboso, F.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Cernuda, I
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    De Marco, R.
    INAF Ist Astrofis & Planetol Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome, Italy..
    Eldrum, S.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Evans, V
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Fedorov, A.
    Inst Rech Astrophys & Planetol, 9 Ave Colonel Roche,BP 4346, F-31028 Toulouse 4, France..
    Hayes, J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Ho, G. C.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Horbury, T. S.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Janitzek, N. P.
    European Space Astron Ctr ESAC, European Space Agcy ESA, Madrid, Spain..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Kollhoff, A.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Kuehl, P.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Kulkarni, S. R.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany.;Deutsch Elektronen Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Lees, W. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Louarn, P.
    Inst Rech Astrophys & Planetol, 9 Ave Colonel Roche,BP 4346, F-31028 Toulouse 4, France..
    Magdalenic, J.
    Katholieke Univ Leuven, Ctr Math Plasma Astrophys, Dept Math, Celestijnenlaan 200B, B-3001 Leuven, Belgium.;Royal Observ Belgium, Solar Terr Ctr Excellence SIDC, B-1180 Brussels, Belgium..
    Maksimovic, M.
    Univ Paris, LESIA, Observ Paris, Univ PSL,CNRS,Sorbonne Univ, 5 Pl Jules Janssen, F-92195 Meudon, France..
    Malandraki, O.
    Natl Observ Athens, Inst Astron Astrophys Space Applicat & Remote Sen, Athens, Greece..
    Martinez, A.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Mason, G. M.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Martin, C.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany.;German Aerosp Ctr DLR, Dept Extrasolar Planets & Atmospheres, Berlin, Germany..
    O'Brien, H.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Owen, C.
    Univ Coll London, Dept Space & Climate Phys, Dorking RH5 6NT, Surrey, England..
    Parra, P.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Prieto Mateo, M.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Ravanbakhsh, A.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany.;Max Planck Inst Solar Syst Res, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Rodriguez-Pacheco, J.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Rodriguez Polo, O.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Sanchez Prieto, S.
    Univ Alcala De Henares, Space Res Grp, Alcala De Henares 28805, Spain..
    Schlemm, C. E.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Seifert, H.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Terasa, J. C.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Tyagi, K.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA.;Univ Colorado, LASP, Boulder, CO 80309 USA..
    Verbeeck, C.
    Royal Observ Belgium, Solar Terr Ctr Excellence SIDC, B-1180 Brussels, Belgium..
    Wimmer-Schweingruber, R. F.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Xu, Z. G.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Yedla, M. K.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany.;Max Planck Inst Solar Syst Res, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Zhukov, A. N.
    Royal Observ Belgium, Solar Terr Ctr Excellence SIDC, B-1180 Brussels, Belgium.;Moscow MV Lomonosov State Univ, Skobeltsyn Inst Nucl Phys, Moscow, Russia..
    Evidence for local particle acceleration in the first recurrent galactic cosmic ray depression observed by Solar Orbiter: The ion event on 19 June 20202021In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 656, article id L10Article in journal (Refereed)
    Abstract [en]

    Context. In mid-June 2020, the Solar Orbiter (SolO) mission reached its first perihelion at 0.51 au and started its cruise phase, with most of the in situ instruments operating continuously.

    Aims. We present the in situ particle measurements of the first proton event observed after the first perihelion obtained by the Energetic Particle Detector (EPD) suite on board SolO. The potential solar and interplanetary (IP) sources of these particles are investigated.

    Methods. Ion observations from similar to 20 keV to similar to 1 MeV are combined with available solar wind data from the Radio and Plasma Waves (RPW) instrument and magnetic field data from the magnetometer on board SolO to evaluate the energetic particle transport conditions and infer the possible acceleration mechanisms through which particles gain energy. We compare > 17-20 MeV ion count rate measurements for two solar rotations, along with the solar wind plasma data available from the Solar Wind Analyser (SWA) and RPW instruments, in order to infer the origin of the observed galactic cosmic ray (GCR) depressions.

    Results. The lack of an observed electron event and of velocity dispersion at various low-energy ion channels and the observed IP structure indicate a local IP source for the low-energy particles. From the analysis of the anisotropy of particle intensities, we conclude that the low-energy ions were most likely accelerated via a local second-order Fermi process. The observed GCR decrease on 19 June, together with the 51.8-1034.0 keV nuc(-1) ion enhancement, was due to a solar wind stream interaction region (SIR). The observation of a similar GCR decrease in the next solar rotation favours this interpretation and constitutes the first observation of a recurrent GCR decrease by SolO. The analysis of the recurrence times of this SIR suggests that it is the same SIR responsible for the He-4 events previously measured in April and May. Finally, we point out that an IP structure more complex than a common SIR cannot be discarded, mainly due to the lack of solar wind temperature measurements and the lack of a higher cadence of solar wind velocity observations.

  • 15.
    Argall, M. R.
    et al.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Paulson, K.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Alm, L.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Rager, A.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Shuster, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Wang, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Torbert, R. B.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA; Southwest Res Inst, San Antonio, TX USA.
    Vaith, H.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Dors, I.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Chutter, M.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Farrugia, C.
    Univ New Hampshire, Ctr Space Sci, Durham, NH USA.
    Burch, J.
    Southwest Res Inst, San Antonio, TX USA.
    Pollock, C.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Giles, B.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Gershman, D.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Lavraud, B.
    Univ Toulouse, CNRS, Inst Rech Astrophys & Planetol, UPS, Toulouse, France..
    Russell, C. T.
    Univ Calif Los Angeles, Earth Planetary & Space Sci, Los Angeles, CA USA..
    Strangeway, R.
    Univ Calif Los Angeles, Earth Planetary & Space Sci, Los Angeles, CA USA..
    Magnes, W.
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Lindqvist, P. -A
    KTH Royal Inst Technol, Stockholm, Sweden.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Ergun, R. E.
    Univ Colorado Boulder, Boulder, CO USA.
    Ahmadi, N.
    Univ Colorado Boulder, Boulder, CO USA.
    Electron Dynamics Within the Electron Diffusion Region of Asymmetric Reconnection2018In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 1, p. 146-162Article in journal (Refereed)
    Abstract [en]

    Abstract: We investigate the agyrotropic nature of electron distribution functions and their substructure to illuminate electron dynamics in a previously reported electron diffusion region (EDR) event. In particular, agyrotropy is examined as a function of energy to reveal detailed finite Larmor radius effects for the first time. It is shown that the previously reported approximate to 66eV agyrotropic "crescent" population that has been accelerated as a result of reconnection is evanescent in nature because it mixes with a denser, gyrotopic background. Meanwhile, accelerated agyrotropic populations at 250 and 500eV are more prominent because the background plasma at those energies is more tenuous. Agyrotropy at 250 and 500eV is also more persistent than at 66eV because of finite Larmor radius effects; agyrotropy is observed 2.5 ion inertial lengths from the EDR at 500eV, but only in close proximity to the EDR at 66eV. We also observe linearly polarized electrostatic waves leading up to and within the EDR. They have wave normal angles near 90 degrees, and their occurrence and intensity correlate with agyrotropy. Within the EDR, they modulate the flux of 500eV electrons travelling along the current layer. The net electric field intensifies the reconnection current, resulting in a flow of energy from the fields into the plasma.

    Plain Language Summary: The process of reconnection involves an explosive transfer of magnetic energy into particle energy. When energetic particles contact modern technology such as satellites, cell phones, or other electronic devices, they can cause random errors and failures. Exactly how particles are energized via reconnection, however, is still unknown. Fortunately, the Magnetospheric Multiscale mission is finally able to detect and analyze reconnection processes. One recent finding is that energized particles take on a crescent-shaped configuration in the vicinity of reconnection and that this crescent shape is related to the energy conversion process. In our paper, we explain why the crescent shape has not been observed until now and inspect particle motions to determine what impact it has on energy conversion. When reconnection heats the plasma, the crescent shape forms from the cool, tenuous particles. As plasmas from different regions mix, dense, nonheated plasma obscures the crescent shape in our observations. The highest-energy particle population created by reconnection, though, also contains features of the crescent shape that are more persistent but appear less dramatically in the data.

    Download full text (pdf)
    fulltext
  • 16.
    Bercic, L.
    et al.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Verscharen, D.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England.;Univ New Hampshire, Space Sci Ctr, 8 Coll Rd, Durham, NH 03824 USA..
    Owen, C. J.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Colomban, L.
    LPC2E CNRS, 3 Ave Rech Sci, F-45071 Orleans 2, France..
    Kretzschmar, M.
    LPC2E CNRS, 3 Ave Rech Sci, F-45071 Orleans 2, France..
    Chust, T.
    Univ Paris Saclay, Observ Paris, Sorbonne Univ, Ecole Polytech, Paris, France..
    Maksimovic, M.
    Univ Paris Diderot, Sorbonne Univ, Sorbonne Paris Cite, Univ PSL,CNRS,LESIA,Observ Paris, 5 Pl Jules Janssen, F-92195 Meudon, France..
    Kataria, D. O.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Anekallu, C.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Behar, E.
    Swedish Inst Space Phys IRF, Kiruna, Sweden.;UCA, CNRS, Lab Lagrange, OCA, Nice, France..
    Berthomier, M.
    Univ Paris Saclay, Observ Paris, Sorbonne Univ, Ecole Polytech, Paris, France..
    Bruno, R.
    INAF IAPS, Via Fosso Cavaliere 100, I-00133 Rome, Italy..
    Fortunato, V
    Planetek Italia, Bari, Italy..
    Kelly, C. W.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lewis, G. R.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Livi, S.
    Southwest Res Inst, San Antonio, TX USA..
    Louarn, P.
    Univ Toulouse, Trap, CNRS, CNES,UPS, Toulouse, France..
    Mele, G.
    Leonardo, Taranto, Italy..
    Nicolaou, G.
    Southwest Res Inst, San Antonio, TX USA..
    Watson, G.
    Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England..
    Wicks, R. T.
    Northumbria Univ, Dept Math Phys & Elect Engn, Newcastle Upon Tyne, Tyne & Wear, England..
    Whistler instability driven by the sunward electron deficit in the solar wind High-cadence Solar Orbiter observations2021In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 656, article id A31Article in journal (Refereed)
    Abstract [en]

    Context. Solar wind electrons play an important role in the energy balance of the solar wind acceleration by carrying energy into interplanetary space in the form of electron heat flux. The heat flux is stored in the complex electron velocity distribution functions (VDFs) shaped by expansion, Coulomb collisions, and field-particle interactions. Aims. We investigate how the suprathermal electron deficit in the anti-strahl direction, which was recently discovered in the near-Sun solar wind, drives a kinetic instability and creates whistler waves with wave vectors that are quasi-parallel to the direction of the background magnetic field.

    Methods. We combined high-cadence measurements of electron pitch-angle distribution functions and electromagnetic waves provided by Solar Orbiter during its first orbit. Our case study is based on a burst-mode data interval from the Electrostatic Analyser System (SWA-EAS) at a distance of 112 R-S (0.52 au) from the Sun, during which several whistler wave packets were detected by Solar Orbiter's Radio and Plasma Waves (RPW) instrument.

    Results. The sunward deficit creates kinetic conditions under which the quasi-parallel whistler wave becomes unstable. We directly test our predictions for the existence of these waves through solar wind observations. We find whistler waves that are quasi-parallel and almost circularly polarised, propagating away from the Sun, coinciding with a pronounced sunward deficit in the electron VDF. The cyclotron-resonance condition is fulfilled for electrons moving in the direction opposite to the direction of wave propagation, with energies corresponding to those associated with the sunward deficit.

    Conclusions. We conclude that the sunward deficit acts as a source of quasi-parallel whistler waves in the solar wind. The quasilinear diffusion of the resonant electrons tends to fill the deficit, leading to a reduction in the total electron heat flux.

  • 17. Berthomier, M.
    et al.
    Fazakerley, A. N.
    Forsyth, C.
    Pottelette, R.
    Alexandrova, O.
    Anastasiadis, A.
    Aruliah, A.
    Blelly, P. -L
    Briand, C.
    Bruno, R.
    Canu, P.
    Cecconi, B.
    Chust, T.
    Daglis, I.
    Davies, J.
    Dunlop, M.
    Fontaine, D.
    Genot, V.
    Gustavsson, B.
    Haerendel, G.
    Hamrin, M.
    Hapgood, M.
    Hess, S.
    Kataria, D.
    Kauristie, K.
    Kemble, S.
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Koskinen, H.
    Lamy, L.
    Lanchester, B.
    Louarn, P.
    Lucek, E.
    Lundin, R.
    Maksimovic, M.
    Manninen, J.
    Marchaudon, A.
    Marghitu, O.
    Marklund, G.
    Milan, S.
    Moen, J.
    Mottez, F.
    Nilsson, H.
    Ostgaard, N.
    Owen, C. J.
    Parrot, M.
    Pedersen, A.
    Perry, C.
    Pincon, J. -L
    Pitout, F.
    Pulkkinen, T.
    Rae, I. J.
    Rezeau, L.
    Roux, A.
    Sandahl, I.
    Sandberg, I.
    Turunen, E.
    Vogt, J.
    Walsh, A.
    Watt, C. E. J.
    Wild, J. A.
    Yamauchi, M.
    Zarka, P.
    Zouganelis, I.
    Alfven: magnetosphere-ionosphere connection explorers2012In: Experimental astronomy, ISSN 0922-6435, E-ISSN 1572-9508, Vol. 33, no 2-3, p. 445-489Article in journal (Refereed)
    Abstract [en]

    The aurorae are dynamic, luminous displays that grace the night skies of Earth's high latitude regions. The solar wind emanating from the Sun is their ultimate energy source, but the chain of plasma physical processes leading to auroral displays is complex. The special conditions at the interface between the solar wind-driven magnetosphere and the ionospheric environment at the top of Earth's atmosphere play a central role. In this Auroral Acceleration Region (AAR) persistent electric fields directed along the magnetic field accelerate magnetospheric electrons to the high energies needed to excite luminosity when they hit the atmosphere. The "ideal magnetohydrodynamics" description of space plasmas which is useful in much of the magnetosphere cannot be used to understand the AAR. The AAR has been studied by a small number of single spacecraft missions which revealed an environment rich in wave-particle interactions, plasma turbulence, and nonlinear acceleration processes, acting on a variety of spatio-temporal scales. The pioneering 4-spacecraft Cluster magnetospheric research mission is now fortuitously visiting the AAR, but its particle instruments are too slow to allow resolve many of the key plasma physics phenomena. The Alfv,n concept is designed specifically to take the next step in studying the aurora, by making the crucial high-time resolution, multi-scale measurements in the AAR, needed to address the key science questions of auroral plasma physics. The new knowledge that the mission will produce will find application in studies of the Sun, the processes that accelerate the solar wind and that produce aurora on other planets.

  • 18.
    Boldu O Farrill Treviño, Joan Jordi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Morooka, Michiko
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Dimmock, Andrew P.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Soucek, J.
    Pisa, D.
    Maksimovic, M.
    Ion-acoustic waves associated with interplanetary shocks2023In: Article in journal (Other academic)
  • 19.
    Breuillard, H.
    et al.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Le Contel, O.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Chust, T.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Berthomier, M.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Retino, A.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Turner, D. L.
    Aerosp Corp, Space Sci Dept, El Segundo, CA 90245 USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Baumjohann, W.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Cozzani, G.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Catapano, F.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Alexandrova, A.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Mirioni, L.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Argall, M. R.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Fischer, D.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Wilder, F. D.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA..
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Varsani, A.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Lindqvist, P. -A
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Marklund, G.
    Royal Inst Technol, Stockholm, Sweden..
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA..
    Goodrich, K. A.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA..
    Ahmadi, N.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA..
    Torbert, R. B.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Needell, G.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Chutter, M.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Rau, D.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Dors, I.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA..
    Magnes, W.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Strangeway, R. J.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA..
    Bromund, K. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Wei, H.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA..
    Plaschke, F.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Anderson, B. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Le, G.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Moore, T. E.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Paterson, W. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Dorelli, J. C.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Avanov, L. A.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Saito, Y.
    Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan..
    Lavraud, B.
    Univ Paul Sabatier, CNRS UMR5277, Inst Rech Astrophys & Planetol, Toulouse, France..
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX USA..
    Mauk, B. H.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Cohen, I. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Fennell, J. F.
    Univ Paris Sud, UPMC Univ Paris 06, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Observ Paris, Paris, France..
    The Properties of Lion Roars and Electron Dynamics in Mirror Mode Waves Observed by the Magnetospheric MultiScale Mission2018In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 1, p. 93-103Article in journal (Refereed)
    Abstract [en]

    Mirror mode waves are ubiquitous in the Earth's magnetosheath, in particular behind the quasi‐perpendicular shock. Embedded in these nonlinear structures, intense lion roars are often observed. Lion roars are characterized by whistler wave packets at a frequency ∼100 Hz, which are thought to be generated in the magnetic field minima. In this study, we make use of the high time resolution instruments on board the Magnetospheric MultiScale mission to investigate these waves and the associated electron dynamics in the quasi‐perpendicular magnetosheath on 22 January 2016. We show that despite a core electron parallel anisotropy, lion roars can be generated locally in the range 0.05–0.2fce by the perpendicular anisotropy of electrons in a particular energy range. We also show that intense lion roars can be observed up to higher frequencies due to the sharp nonlinear peaks of the signal, which appear as sharp spikes in the dynamic spectra. As a result, a high sampling rate is needed to estimate correctly their amplitude, and the latter might have been underestimated in previous studies using lower time resolution instruments. We also present for the first‐time 3‐D high time resolution electron velocity distribution functions in mirror modes. We demonstrate that the dynamics of electrons trapped in the mirror mode structures are consistent with the Kivelson and Southwood (1996) model. However, these electrons can also interact with the embedded lion roars: first signatures of electron quasi‐linear pitch angle diffusion and possible signatures of nonlinear interaction with high‐amplitude wave packets are presented. These processes can lead to electron untrapping from mirror modes.

    Download full text (pdf)
    fulltext
  • 20.
    Breuillard, H.
    et al.
    CNRS, LPP, UMR, Paris, France..
    Le Contel, O.
    CNRS, LPP, UMR, Paris, France..
    Retino, A.
    CNRS, LPP, UMR, Paris, France..
    Chasapis, A.
    Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Chust, T.
    CNRS, LPP, UMR, Paris, France..
    Mirioni, L.
    CNRS, LPP, UMR, Paris, France..
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Wilder, F. D.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Cohen, I.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Royal Inst Technol, Alfven Lab, Stockholm, Sweden.
    Marklund, G. T.
    Royal Inst Technol, Alfven Lab, Stockholm, Sweden..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA..
    Torbert, R. B.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Ergun, R. E.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Goodrich, K. A.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Macri, J.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Needell, J.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Chutter, M.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Rau, D.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Dors, I.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA..
    Magnes, W.
    Austrian Acad Sci, Space Res Inst IWF, Graz, Austria..
    Strangeway, R. J.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA..
    Bromund, K. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Plaschke, F.
    Austrian Acad Sci, Space Res Inst IWF, Graz, Austria..
    Fischer, D.
    Austrian Acad Sci, Space Res Inst IWF, Graz, Austria..
    Leinweber, H. K.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA..
    Anderson, B. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Le, G.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Slavin, J. A.
    Univ Michigan, Dept Climate & Space Sci & Engn, Ann Arbor, MI 48109 USA..
    Kepko, E. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Baumjohann, W.
    Austrian Acad Sci, Space Res Inst IWF, Graz, Austria..
    Mauk, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Fuselier, S. A.
    Univ Texas San Antonio, Dept Phys & Astron, San Antonio, TX USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst IWF, Graz, Austria..
    Multispacecraft analysis of dipolarization fronts and associated whistler wave emissions using MMS data2016In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 14, p. 7279-7286Article in journal (Refereed)
    Abstract [en]

    Dipolarization fronts (DFs), embedded in bursty bulk flows, play a crucial role in Earth's plasma sheet dynamics because the energy input from the solar wind is partly dissipated in their vicinity. This dissipation is in the form of strong low-frequency waves that can heat and accelerate energetic electrons up to the high-latitude plasma sheet. However, the dynamics of DF propagation and associated low-frequency waves in the magnetotail are still under debate due to instrumental limitations and spacecraft separation distances. In May 2015 the Magnetospheric Multiscale (MMS) mission was in a string-of-pearls configuration with an average intersatellite distance of 160km, which allows us to study in detail the microphysics of DFs. Thus, in this letter we employ MMS data to investigate the properties of dipolarization fronts propagating earthward and associated whistler mode wave emissions. We show that the spatial dynamics of DFs are below the ion gyroradius scale in this region (approximate to 500km), which can modify the dynamics of ions in the vicinity of the DF (e.g., making their motion nonadiabatic). We also show that whistler wave dynamics have a temporal scale of the order of the ion gyroperiod (a few seconds), indicating that the perpendicular temperature anisotropy can vary on such time scales.

  • 21.
    Breuillard, H.
    et al.
    Univ Paris Sud, Sorbonne Univ, Ecole Polytech, Lab Phys Plasmas,UMR7648,CNRS, Paris, France.
    Matteini, L.
    UPMC Univ Paris 06, Univ Paris Diderot, PSL Res Univ, LESIA Observ Paris,CNRS, Meudon, France.
    Argall, M. R.
    Univ New Hampshire, Durham, NH 03824 USA.
    Sahraoui, F.
    Univ Paris Sud, Sorbonne Univ, Ecole Polytech, Lab Phys Plasmas,UMR7648,CNRS, Paris, France.
    Andriopoulou, M.
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Le Contel, O.
    Univ Paris Sud, Sorbonne Univ, Ecole Polytech, Lab Phys Plasmas,UMR7648,CNRS, Paris, France.
    Retino, A.
    Univ Paris Sud, Sorbonne Univ, Ecole Polytech, Lab Phys Plasmas,UMR7648,CNRS, Paris, France.
    Mirioni, L.
    Univ Paris Sud, Sorbonne Univ, Ecole Polytech, Lab Phys Plasmas,UMR7648,CNRS, Paris, France.
    Huang, S. Y.
    Wuhan Univ, Sch Elect & Informat, Beijing, Peoples R China.
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Wilder, F. D.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Goodrich, K. A.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Ahmadi, N.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Yordanova, Emiliya
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Turner, D. L.
    Aerosp Corp, Space Sci Dept, El Segundo, CA 90245 USA.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Chasapis, A.
    Univ Delaware, Newark, DE USA.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.
    Torbert, R. B.
    Univ New Hampshire, Durham, NH 03824 USA.
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA USA.
    Magnes, W.
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Strangeway, R. J.
    Plaschke, F.
    Austrian Acad Sci, Space Res Inst, Graz, Austria.
    Moore, T. E.
    Giles, B. L.
    Paterson, W. R.
    Pollock, C. J.
    Lavraud, B.
    Univ Paul Sabatier, CNRS UMR5277, IRAP, Toulouse, France.
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX USA.
    Cohen, I. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA.
    New Insights into the Nature of Turbulence in the Earth's Magnetosheath Using Magnetospheric MultiScale Mission Data2018In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 859, no 2, article id 127Article in journal (Refereed)
    Abstract [en]

    The Earth's magnetosheath, which is characterized by highly turbulent fluctuations, is usually divided into two regions of different properties as a function of the angle between the interplanetary magnetic field and the shock normal. In this study, we make use of high-time resolution instruments on board the Magnetospheric MultiScale spacecraft to determine and compare the properties of subsolar magnetosheath turbulence in both regions, i. e., downstream of the quasi-parallel and quasi-perpendicular bow shocks. In particular, we take advantage of the unprecedented temporal resolution of the Fast Plasma Investigation instrument to show the density fluctuations down to sub-ion scales for the first time. We show that the nature of turbulence is highly compressible down to electron scales, particularly in the quasi-parallel magnetosheath. In this region, the magnetic turbulence also shows an inertial (Kolmogorov-like) range, indicating that the fluctuations are not formed locally, in contrast with the quasi-perpendicular magnetosheath. We also show that the electromagnetic turbulence is dominated by electric fluctuations at sub-ion scales (f > 1Hz) and that magnetic and electric spectra steepen at the largest-electron scale. The latter indicates a change in the nature of turbulence at electron scales. Finally, we show that the electric fluctuations around the electron gyrofrequency are mostly parallel in the quasi-perpendicular magnetosheath, where intense whistlers are observed. This result suggests that energy dissipation, plasma heating, and acceleration might be driven by intense electrostatic parallel structures/waves, which can be linked to whistler waves.

  • 22.
    Burch, J. L.
    et al.
    Southwest Res Inst, San Antonio, TX USA..
    Torbert, R. B.
    Southwest Res Inst, San Antonio, TX USA.;Univ New Hampshire, Durham, NH 03824 USA..
    Phan, T. D.
    Univ Calif Berkeley, Berkeley, CA 94720 USA..
    Chen, L. -J
    Moore, T. E.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Ergun, R. E.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Eastwood, J. P.
    Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England..
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Cassak, P. A.
    W Virginia Univ, Morgantown, WV 26506 USA..
    Argall, M. R.
    Univ New Hampshire, Durham, NH 03824 USA..
    Wang, S.
    Univ Maryland, College Pk, MD 20742 USA..
    Hesse, M.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Mauk, B. H.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, Los Angeles, CA USA..
    Drake, J. F.
    Univ Maryland, College Pk, MD 20742 USA..
    Shay, M. A.
    Univ Delaware, Newark, DE USA..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Marklund, G.
    Royal Inst Technol, Stockholm, Sweden..
    Wilder, F. D.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Young, D. T.
    Southwest Res Inst, San Antonio, TX USA..
    Torkar, K.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Goldstein, J.
    Southwest Res Inst, San Antonio, TX USA..
    Dorelli, J. C.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Avanov, L. A.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Oka, M.
    Univ Calif Berkeley, Berkeley, CA 94720 USA..
    Baker, D. N.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Jaynes, A. N.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Goodrich, K. A.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Cohen, I. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Turner, D. L.
    Aerosp Corp, El Segundo, CA 90245 USA..
    Fennell, J. F.
    Aerosp Corp, El Segundo, CA 90245 USA..
    Blake, J. B.
    Aerosp Corp, El Segundo, CA 90245 USA..
    Clemmons, J.
    Aerosp Corp, El Segundo, CA 90245 USA..
    Goldman, M.
    Univ Colorado, Boulder, CO 80309 USA..
    Newman, D.
    Univ Colorado, Boulder, CO 80309 USA..
    Petrinec, S. M.
    Lockheed Martin Adv Technol Ctr, Palo Alto, CA USA..
    Trattner, K. J.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Lavraud, B.
    Inst Rech Astrophys & Planetol, Toulouse, France..
    Reiff, P. H.
    Rice Univ, Dept Phys & Astron, Houston, TX USA..
    Baumjohann, W.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Magnes, W.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Steller, M.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Lewis, W.
    Southwest Res Inst, San Antonio, TX USA..
    Saito, Y.
    Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229, Japan..
    Coffey, V.
    NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA..
    Chandler, M.
    NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA..
    Electron-scale measurements of magnetic reconnection in space2016In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 352, no 6290, p. 1189-+Article, review/survey (Refereed)
    Abstract [en]

    Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy is converted into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments and in laboratory plasmas. Using measurements with very high time resolution, NASA's Magnetospheric Multiscale (MMS) mission has found direct evidence for electron demagnetization and acceleration at sites along the sunward boundary of Earth's magnetosphere where the interplanetary magnetic field reconnects with the terrestrial magnetic field. We have (i) observed the conversion of magnetic energy to particle energy; (ii) measured the electric field and current, which together cause the dissipation of magnetic energy; and (iii) identified the electron population that carries the current as a result of demagnetization and acceleration within the reconnection diffusion/dissipation region.

  • 23.
    Cao, D.
    et al.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Fu, H. S.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Cao, J. B.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Wang, T. Y.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Chen, Z. Z.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Peng, F. Z.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Huang, S. Y.
    Wuhan Univ, Sch Elect & Informat, Wuhan, Peoples R China.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Russell, C. T.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Lindqvist, P. -A
    Torbert, R. B.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.
    Ergun, R. E.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.
    Le Contel, O.
    UPMC, Ecole Polytech, CNRS, Lab Phys Plasmas, Palaiseau, France.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.
    MMS observations of whistler waves in electron diffusion region2017In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 44, no 9, p. 3954-3962Article in journal (Refereed)
    Abstract [en]

    Whistler waves that can produce anomalous resistivity by affecting electrons' motion have been suggested as one of the mechanisms responsible for magnetic reconnection in the electron diffusion region (EDR). Such type of waves, however, has rarely been observed inside the EDR so far. In this study, we report such an observation by Magnetospheric Multiscale (MMS) mission. We find large-amplitude whistler waves propagating away from the X line with a very small wave-normal angle. These waves are probably generated by the perpendicular temperature anisotropy of the -300eV electrons inside the EDR, according to our analysis of dispersion relation and cyclotron resonance condition; they significantly affect the electron-scale dynamics of magnetic reconnection and thus support previous simulations.

  • 24.
    Carbone, F.
    et al.
    Univ Calabria, Natl Res Council, Inst Atmospher Pollut Res, I-87036 Arcavacata Di Rende, Italy..
    Sorriso-Valvo, Luca
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Ist Sci & Tecnol Plasmi, CNR, Via Amendola 122-D, I-70126 Bari, Italy.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Steinvall, Konrad
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vecchio, A.
    Univ Paris Diderot, Sorbonne Univ, Univ PSL, Observ Paris, Sorbonne Paris Cite,5 Pl Jules Janssen, F-92195 Meudon, France.;Radboud Univ Nijmegen, Res Inst Math Astrophys & Particle Phys, Nijmegen, Netherlands..
    Telloni, D.
    Natl Inst Astrophys, Astrophys Observ Torino, Turin, Italy..
    Yordanova, Emiliya
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Edberg, Niklas J. T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Eriksson, Anders I.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Johansson, Erik P. G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vásconez, C. L.
    Escuela Politec Nacl, Dept Fis, Ladron de Guevara E11-253, Quito 170525, Ecuador..
    Maksimovic, M.
    Radboud Univ Nijmegen, Res Inst Math Astrophys & Particle Phys, Nijmegen, Netherlands..
    Bruno, R.
    Natl Inst Astrophys INAF, Inst Space Astrophys & Planetol IAPS, Via Fosso del Cavaliere 100, I-00133 Rome, Italy..
    D'Amicis, R.
    Natl Inst Astrophys INAF, Inst Space Astrophys & Planetol IAPS, Via Fosso del Cavaliere 100, I-00133 Rome, Italy..
    Bale, S. D.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.;Univ Calif Berkeley, Phys Dept, Berkeley, CA 94720 USA..
    Chust, T.
    Univ Paris Saclay, Observ Paris, Sorbonne Univ, Ecole Polytech,LPP,CNRS, Paris, France..
    Krasnoselskikh, V.
    CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France..
    Kretzschmar, M.
    CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France.;Univ Orleans, Orleans, France..
    Lorfèvre, E.
    CNES, 18 Ave Edouard Belin, F-31400 Toulouse, France..
    Plettemeier, D.
    Tech Univ Dresden, Wurzburger Str 35, D-01187 Dresden, Germany..
    Soucek, J.
    Czech Acad Sci, Inst Atmospher Phys, Prague, Czech Republic..
    Steller, M.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Stverák, S.
    Czech Acad Sci, Inst Atmospher Phys, Prague, Czech Republic.;Czech Acad Sci, Astron Inst, Prague, Czech Republic..
    Trávnicek, P.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.;Czech Acad Sci, Inst Atmospher Phys, Prague, Czech Republic..
    Vaivads, A.
    CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France.;Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Space & Plasma Phys, Stockholm, Sweden..
    Horbury, T. S.
    Imperial Coll London, Blackett Lab, Space & Atmospher Phys, London SW7 2AZ, England..
    O'Brien, H.
    Imperial Coll London, Blackett Lab, Space & Atmospher Phys, London SW7 2AZ, England..
    Angelini, V.
    Imperial Coll London, Blackett Lab, Space & Atmospher Phys, London SW7 2AZ, England..
    Evans, V.
    Imperial Coll London, Blackett Lab, Space & Atmospher Phys, London SW7 2AZ, England..
    Statistical study of electron density turbulence and ion-cyclotron waves in the inner heliosphere: Solar Orbiter observations2021In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 656, article id A16Article in journal (Refereed)
    Abstract [en]

    Context. The recently released spacecraft potential measured by the RPW instrument on board Solar Orbiter has been used to estimate the solar wind electron density in the inner heliosphere.

    Aims. The measurement of the solar wind’s electron density, taken in June 2020, has been analysed to obtain a thorough characterization of the turbulence and intermittency properties of the fluctuations. Magnetic field data have been used to describe the presence of ion-scale waves.

    Methods. To study and quantify the properties of turbulence, we extracted selected intervals. We used empirical mode decomposition to obtain the generalized marginal Hilbert spectrum, equivalent to the structure functions analysis, which additionally reduced issues typical of non-stationary, short time series. The presence of waves was quantitatively determined by introducing a parameter describing the time-dependent, frequency-filtered wave power.

    Results. A well-defined inertial range with power-law scalng was found almost everywhere in the sample studied. However, the Kolmogorov scaling and the typical intermittency effects are only present in fraction of the samples. Other intervals have shallower spectra and more irregular intermittency, which are not described by models of turbulence. These are observed predominantly during intervals of enhanced ion frequency wave activity. Comparisons with compressible magnetic field intermittency (from the MAG instrument) and with an estimate of the solar wind velocity (using electric and magnetic field) are also provided to give general context and help determine the cause of these anomalous fluctuations.

  • 25.
    Catapano, Filomena
    et al.
    Univ Paris Sud, Lab Phys Plasmas, CNRS, Ecole Polytech,Sorbonne Univ,Observ Paris, Paris, France.;Univ Calabria, Dipartimento Fis, Arcavacata Di Rende, Italy..
    Retino, Alessandro
    Univ Paris Sud, Lab Phys Plasmas, CNRS, Ecole Polytech,Sorbonne Univ,Observ Paris, Paris, France..
    Zimbardo, Gaetano
    Univ Calabria, Dipartimento Fis, Arcavacata Di Rende, Italy..
    Alexandrova, Alexandra
    Univ Paris Sud, Lab Phys Plasmas, CNRS, Ecole Polytech,Sorbonne Univ,Observ Paris, Paris, France..
    Cohen, Ian J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Turner, Drew L.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Le Contel, Olivier
    Univ Paris Sud, Lab Phys Plasmas, CNRS, Ecole Polytech,Sorbonne Univ,Observ Paris, Paris, France..
    Cozzani, Giulia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Perri, Silvia
    Univ Calabria, Dipartimento Fis, Arcavacata Di Rende, Italy..
    Greco, Antonella
    Univ Calabria, Dipartimento Fis, Arcavacata Di Rende, Italy..
    Breuillard, Hugo
    Univ Paris Sud, Lab Phys Plasmas, CNRS, Ecole Polytech,Sorbonne Univ,Observ Paris, Paris, France.;CNRS, Lab Phys & Chim Environm & Espace, Orleans, France..
    Delcourt, Dominique
    CNRS, Lab Phys & Chim Environm & Espace, Orleans, France..
    Mirioni, Laurent
    Univ Paris Sud, Lab Phys Plasmas, CNRS, Ecole Polytech,Sorbonne Univ,Observ Paris, Paris, France..
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Giles, Barbara L.
    Goddard Space Flight Ctr, Greenbelt, MD USA..
    Mauk, Barry H.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Fuselier, Stephen A.
    Southwest Res Inst, San Antonio, TX USA.;Univ Texas San Antonio, San Antonio, TX USA..
    Torbert, Roy B.
    Univ New Hampshire, Durham, NH 03824 USA..
    Russell, Christopher T.
    Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA..
    Lindqvist, Per A.
    Royal Inst Technol, Stockholm, Sweden..
    Ergun, Robert E.
    Univ Colorado, LASP, Boulder, CO 80309 USA..
    Moore, Thomas
    Goddard Space Flight Ctr, Greenbelt, MD USA..
    Burch, James L.
    Southwest Res Inst, San Antonio, TX USA..
    In Situ Evidence of Ion Acceleration between Consecutive Reconnection Jet Fronts2021In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 908, no 1, article id 73Article in journal (Refereed)
    Abstract [en]

    Processes driven by unsteady reconnection can efficiently accelerate particles in many astrophysical plasmas. An example is the reconnection jet fronts in an outflow region. We present evidence of suprathermal ion acceleration between two consecutive reconnection jet fronts observed by the Magnetospheric Multiscale mission in the terrestrial magnetotail. An earthward propagating jet is approached by a second faster jet. Between the jets, the thermal ions are mostly perpendicular to magnetic field, are trapped, and are gradually accelerated in the parallel direction up to 150 keV. Observations suggest that ions are predominantly accelerated by a Fermi-like mechanism in the contracting magnetic bottle formed between the two jet fronts. The ion acceleration mechanism is presumably efficient in other environments where jet fronts produced by variable rates of reconnection are common and where the interaction of multiple jet fronts can also develop a turbulent environment, e.g., in stellar and solar eruptions.

  • 26. Chasapis, A.
    et al.
    Retino, A.
    Sahraoui, F.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Sundkvist, D.
    Greco, A.
    Sorriso-Valvo, L.
    Canu, P.
    Thin Current Sheets and Associated Electron Heating in Turbulent Space Plasma2015In: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 804, no 1, article id L1Article in journal (Refereed)
    Abstract [en]

    Intermittent structures, such as thin current sheets, are abundant in turbulent plasmas. Numerical simulations indicate that such current sheets are important sites of energy dissipation and particle heating occurring at kinetic scales. However, direct evidence of dissipation and associated heating within current sheets is scarce. Here, we show a new statistical study of local electron heating within proton-scale current sheets by using high-resolution spacecraft data. Current sheets are detected using the Partial Variance of Increments (PVI) method which identifies regions of strong intermittency. We find that strong electron heating occurs in high PVI (>3) current sheets while no significant heating occurs in low PVI cases (<3), indicating that the former are dominant for energy dissipation. Current sheets corresponding to very high PVI (>5) show the strongest heating and most of the time are consistent with ongoing magnetic reconnection. This suggests that reconnection is important for electron heating and dissipation at kinetic scales in turbulent plasmas.

  • 27.
    Chasapis, Alexandros
    et al.
    Univ Delaware, Newark, DC USA..
    Matthaeus, W. H.
    Univ Delaware, Newark, DC USA..
    Parashar, T. N.
    Univ Delaware, Newark, DC USA..
    LeContel, O.
    Lab Phys Plasmas, Paris, France..
    Retino, A.
    Lab Phys Plasmas, Paris, France..
    Breuillard, H.
    Lab Phys Plasmas, Paris, France..
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lavraud, B.
    Univ Toulouse UPS, Inst Rech Astrophys & Plantol, Toulouse, France.;Ctr Natl Rech Sci, UMR 5277, Toulouse, France..
    Eriksson, Elin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Moore, T. E.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA..
    Torbert, R. B.
    Univ New Hampshire, Durham, NH 03824 USA..
    Lindqvist, P. -A
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO USA..
    Marklund, G.
    Royal Inst Technol, Stockholm, Sweden..
    Goodrich, K. A.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO USA..
    Wilder, F. D.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO USA..
    Chutter, M.
    Univ New Hampshire, Durham, NH 03824 USA..
    Needell, J.
    Univ New Hampshire, Durham, NH 03824 USA..
    Rau, D.
    Univ New Hampshire, Durham, NH 03824 USA..
    Dors, I.
    Univ New Hampshire, Durham, NH 03824 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA USA..
    Le, G.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Magnes, W.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Strangeway, R. J.
    Univ Calif Los Angeles, Los Angeles, CA USA..
    Bromund, K. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Leinweber, H. K.
    Univ Calif Los Angeles, Los Angeles, CA USA..
    Plaschke, F.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Fischer, D.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Anderson, B. J.
    Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA..
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Paterson, W. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Avanov, L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Saito, Y.
    Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan..
    Electron Heating at Kinetic Scales in Magnetosheath Turbulence2017In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 836, no 2, article id 247Article in journal (Refereed)
    Abstract [en]

    We present a statistical study of coherent structures at kinetic scales, using data from the Magnetospheric Multiscale mission in the Earth's magnetosheath. We implemented the multi-spacecraft partial variance of increments (PVI) technique to detect these structures, which are associated with intermittency at kinetic scales. We examine the properties of the electron heating occurring within such structures. We find that, statistically, structures with a high PVI index are regions of significant electron heating. We also focus on one such structure, a current sheet, which shows some signatures consistent with magnetic reconnection. Strong parallel electron heating coincides with whistler emissions at the edges of the current sheet.

  • 28.
    Chasapis, Alexandros
    et al.
    Univ Delaware, Newark, DE 19716 USA.
    Matthaeus, W. H.
    Univ Delaware, Newark, DE 19716 USA.
    Parashar, T. N.
    Univ Delaware, Newark, DE 19716 USA.
    Wan, M.
    South Univ Sci & Technol China, Shenzhen, Guangdong, Peoples R China.
    Haggerty, C. C.
    Univ Delaware, Newark, DE 19716 USA.
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Paterson, W. R.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Torbert, R. B.
    Univ New Hampshire, Durham, NH 03824 USA.
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA USA.
    Lindqvist, P. -A
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Moore, T. E.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.
    In Situ Observation of Intermittent Dissipation at Kinetic Scales in the Earth's Magnetosheath2018In: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 856, no 1, article id L19Article in journal (Refereed)
    Abstract [en]

    We present a study of signatures of energy dissipation at kinetic scales in plasma turbulence based on observations by the Magnetospheric Multiscale mission (MMS) in the Earth's magnetosheath. Using several intervals, and taking advantage of the high-resolution instrumentation on board MMS, we compute and discuss several statistical measures of coherent structures and heating associated with electrons, at previously unattainable scales in space and time. We use the multi-spacecraft Partial Variance of Increments (PVI) technique to study the intermittent structure of the magnetic field. Furthermore, we examine a measure of dissipation and its behavior with respect to the PVI as well as the current density. Additionally, we analyze the evolution of the anisotropic electron temperature and non-Maxwellian features of the particle distribution function. From these diagnostics emerges strong statistical evidence that electrons are preferentially heated in subproton-scale regions of strong electric current density, and this heating is preferentially in the parallel direction relative to the local magnetic field. Accordingly, the conversion of magnetic energy into electron kinetic energy occurs more strongly in regions of stronger current density, a finding consistent with several kinetic plasma simulation studies and hinted at by prior studies using lower resolution Cluster observations.

  • 29. Chen, L. -J
    et al.
    Hesse, M.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Wang, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Gershman, D.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Burch, J.
    Southwest Res Inst, San Antonio, TX USA..
    Bessho, N.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Torbert, R. B.
    Southwest Res Inst, San Antonio, TX USA.;Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Giles, B.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Webster, J.
    Rice Univ, Dept Phys & Astron, Houston, TX USA..
    Pollock, C.
    Denali Sci, Healy, AK USA..
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Moore, T.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Paterson, W.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Lavraud, B.
    Univ Toulouse, Inst Rech Astrophys & Planetol, Toulouse, France.;CNRS, UMR 5277, Toulouse, France..
    Strangeway, R.
    Univ Calif Los Angeles, Earth Planetary & Space Sci, Los Angeles, CA USA..
    Russell, C.
    Univ Calif Los Angeles, Earth Planetary & Space Sci, Los Angeles, CA USA..
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Avanov, L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations2017In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 5, p. 5235-5246Article in journal (Refereed)
    Abstract [en]

    An electron diffusion region (EDR) in magnetic reconnection with a guide magnetic field approximately 0.2 times the reconnecting component is encountered by the four Magnetospheric Multiscale spacecraft at the Earth's magnetopause. The distinct substructures in the EDR on both sides of the reconnecting current sheet are visualized with electron distribution functions that are 2 orders of magnitude higher cadence than ever achieved to enable the following new findings: (1) Motion of the demagnetized electrons plays an important role to sustain the reconnection current and contributes to the dissipation due to the nonideal electric field, (2) the finite guide field dominates over the Hall magnetic field in an electron-scale region in the exhaust and modifies the electron flow dynamics in the EDR, (3) the reconnection current is in part carried by inflowing field-aligned electrons in the magnetosphere part of the EDR, and (4) the reconnection electric field measured by multiple spacecraft is uniform over at least eight electron skin depths and corresponds to a reconnection rate of approximately 0.1. The observations establish the first look at the structure of the EDR under a weak but not negligible guide field.

  • 30. Chen, L. -J
    et al.
    Wang, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA;Univ Maryland, Dept Astron, College Pk, MD 20742 USA.
    Hesse, M.
    Univ Bergen, Dept Phys & Technol, Bergen, Norway.
    Ergun, R. E.
    Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA.
    Moore, T.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Giles, B.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Bessho, N.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA;Univ Maryland, Dept Astron, College Pk, MD 20742 USA.
    Russell, C.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA.
    Burch, J.
    Southwest Res Inst, San Antonio, TX USA.
    Torbert, R. B.
    Southwest Res Inst, San Antonio, TX USA;Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.
    Genestreti, K. J.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA.
    Paterson, W.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Pollock, C.
    Denali Sci, Healy, AK USA.
    Lavraud, B.
    Univ Toulouse UPS, Inst Rech Astrophys & Planetol, CNRS, CNES, Toulouse, France.
    Le Contel, O.
    Univ Paris Sud, Lab Phys Plasmas UMR7648, Ecole Polytech, CNRS,Sorbonne Univ,Observ Paris, Paris, France.
    Strangeway, R.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Electron Diffusion Regions in Magnetotail Reconnection Under Varying Guide Fields2019In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 46, no 12, p. 6230-6238Article in journal (Refereed)
    Abstract [en]

    Kinetic structures of electron diffusion regions (EDRs) under finite guide fields in magnetotail reconnection are reported. The EDRs with guide fields 0.14-0.5 (in unit of the reconnecting component) are detected by the Magnetospheric Multiscale spacecraft. The key new features include the following: (1) cold inflowing electrons accelerated along the guide field and demagnetized at the magnetic field minimum while remaining a coherent population with a low perpendicular temperature, (2) wave fluctuations generating strong perpendicular electron flows followed by alternating parallel flows inside the reconnecting current sheet under an intermediate guide field, and (3) gyrophase bunched electrons with high parallel speeds leaving the X-line region. The normalized reconnection rates for the three EDRs range from 0.05 to 0.3. The measurements reveal that finite guide fields introduce new mechanisms to break the electron frozen-in condition. Plain Language Summary Magnetic reconnection plays a crucial role in the dynamics of the terrestrial magnetotail. For reconnection to occur, the plasma must decouple from the magnetic field. The bounce motion of particles in the magnetotail current sheet is regarded as a key to this decoupling for cases when the current sheet has no magnetic field along the direction of the current. This paper reports that while bounce motion remains relevant when a finite magnetic field is present along the current, new mechanisms to decouple electrons from the magnetic field are introduced, and new open questions unfold. The observations are based on measurements from the Magnetospheric Multiscale mission. The mission's unprecedented high cadence electron data make possible the revelation of the new mechanisms. The results reported in this paper expand the frontiers of our knowledge on magnetotail reconnection and have major implications on the fundamental physics of magnetic reconnection in all plasma systems where binary collisions are not effective, including solar, astrophysical, and laboratory plasmas. Rapid dissemination of the results will set the ground for advances in magnetic reconnection research.

    Download full text (pdf)
    FULLTEXT01
  • 31. Chen, L. -J
    et al.
    Wang, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA;Univ Maryland, Dept Astron, College Pk, MD 20747 USA.
    Wilson, L. B. , I I I
    Schwartz, S.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80305 USA.
    Bessho, N.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA;Univ Maryland, Dept Astron, College Pk, MD 20747 USA.
    Moore, T.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Gershman, D.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Giles, B.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Malaspina, D.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80305 USA.
    Wilder, F. D.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80305 USA.
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80305 USA.
    Hesse, M.
    Univ Bergen, N-5020 Bergen, Norway.
    Lai, H.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA.
    Russell, C.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA.
    Strangeway, R.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA.
    Torbert, R. B.
    Southwest Res Inst, San Antonio, TX 78238 USA.
    Vinas, A. F.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Burch, J.
    Southwest Res Inst, San Antonio, TX 78238 USA.
    Lee, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Pollock, C.
    Denali Sci, Healy, AK 99743 USA.
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Paterson, W.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Ahmadi, N.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80305 USA.
    Goodrich, K.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80305 USA.
    Lavraud, B.
    Univ Toulouse UPS, Inst Rech Astrophys & Planetol, CNRS, CNES, F-31028 Toulouse 4, France.
    Le Contel, O.
    Univ Paris Sud, Observ Paris, Lab Phys Plasmas, UMR7648,CNRS,Ecole Polytech,Sorbonne Univ, F-91128 Palaiseau, France.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lindqvist, P. -A
    Boardsen, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA;Univ Maryland, Dept Astron, College Pk, MD 20747 USA.
    Wei, H.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA.
    Le, A.
    Los Alamos Natl Lab, Los Alamos, NM 87545 USA.
    Avanov, L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA;Univ Maryland, Dept Astron, College Pk, MD 20747 USA.
    Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 22, article id 225101Article in journal (Refereed)
    Abstract [en]

    Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.

  • 32.
    Chen, L-J
    et al.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Wang, S.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Le Contel, O.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, CNRS,Ecole Polytech, F-91128 Paris, France..
    Rager, A.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Hesse, M.
    Univ Bergen, N-5020 Bergen, Norway..
    Drake, J.
    Univ Maryland, College Pk, MD 20747 USA..
    Dorelli, J.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Ng, J.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Bessho, N.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Wilson, Lynn B., III
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Moore, T.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Giles, B.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Paterson, W.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA..
    Lavraud, B.
    Univ Toulouse UPS, CNRS, CNES, Inst Rech Astrophys & Planetol, F-31027 Toulouse 4, France..
    Genestreti, K.
    Univ New Hampshire, Durham, NH 03824 USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Ergun, R. E.
    Univ Colorado, Boulder, CO 80305 USA..
    Torbert, R. B.
    Univ New Hampshire, Durham, NH 03824 USA..
    Burch, J.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Pollock, C.
    Denali Sci, Healy, AK 99743 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Lindqvist, P-A
    KTH Royal Inst Technol, SE-11428 Stockholm, Sweden..
    Avanov, L.
    NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA.;Univ Maryland, College Pk, MD 20747 USA..
    Lower-Hybrid Drift Waves Driving Electron Nongyrotropic Heating and Vortical Flows in a Magnetic Reconnection Layer2020In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 125, no 2, article id 025103Article in journal (Refereed)
    Abstract [en]

    We report measurements of lower-hybrid drift waves driving electron heating and vortical flows in an electron-scale reconnection layer under a guide field. Electrons accelerated by the electrostatic potential of the waves exhibit perpendicular and nongyrotropic heating. The vortical flows generate magnetic field perturbations comparable to the guide field magnitude. The measurements reveal a new regime of electron-wave interaction and how this interaction modifies the electron dynamics in the reconnection layer.

  • 33.
    Chen, Z. Z.
    et al.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Fu, H. S.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Liu, C. M.
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China.
    Wang, T. Y.
    STFC, RAL Space, Didcot, Oxon, England.
    Ergun, R. E.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.
    Cozzani, G.
    UPMC, Ecole Polytech, CNRS, Lab Phys Plasmas, Palaiseau, France.
    Huang, S. Y.
    Wuhan Univ, Sch Elect Informat, Wuhan, Hubei, Peoples R China.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Le Contel, O.
    UPMC, Ecole Polytech, CNRS, Lab Phys Plasmas, Palaiseau, France.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA.
    Electron-Driven Dissipation in a Tailward Flow Burst2019In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 46, no 11, p. 5698-5706Article in journal (Refereed)
    Abstract [en]

    Traditionally, the magnetotail flow burst outside the diffusion region is known to carry ions and electrons together (V-i = V-e), with the frozen-in condition well satisfied (E + V-e x B = 0). Such picture, however, may not be true, based on our analyses of the high-resolution MMS (Magnetospheric Multiscale mission) data. We find that inside the flow burst the electrons and ions can be decoupled (V-e not equal V-i), with the electron speed 5 times larger than the ion speed. Such super-Alfvenic electron jet, having scale of 10 d(i) (ion inertial length) in X-GSM direction, is associated with electron demagnetization (E + V-e x B not equal 0), electron agyrotropy (crescent distribution), and O-line magnetic topology but not associated with the flow reversal and X-line topology; it can cause strong energy dissipation and electron heating. We quantitatively analyze the dissipation and find that it is primarily attributed to lower hybrid drift waves. These results emphasize the non-MHD (magnetohydrodynamics) behaviors of magnetotail flow bursts and the role of lower hybrid drift waves in dissipating energies.

  • 34.
    Chust, T.
    et al.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Kretzschmar, M.
    Univ Orleans, CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France..
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Le Contel, O.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Retino, A.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Alexandrova, A.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Berthomier, M.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Hadid, L. Z.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Sahraoui, F.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Jeandet, A.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Leroy, P.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Pellion, J-C
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Bouzid, V
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Katra, B.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Piberne, R.
    Sorbonne Univ, Univ Paris Saclay, Observ Paris, Ecole Polytech,LPP,CNRS, Paris, France..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Royal Inst Technol, Sch Elect Engn & Comp Sci, Dept Space & Plasma Phys, Stockholm, Sweden..
    Krasnoselskikh, V
    Univ Orleans, CNRS, LPC2E, 3A Ave Rech Sci, Orleans, France..
    Soucek, J.
    Czech Acad Sci, Dept Space Phys, Inst Atmospher Phys, Prague, Czech Republic..
    Santolik, O.
    Czech Acad Sci, Dept Space Phys, Inst Atmospher Phys, Prague, Czech Republic.;Charles Univ Prague, Fac Math & Phys, Prague, Czech Republic..
    Lorfevre, E.
    CNES, 18 Ave Edouard Belin, F-31400 Toulouse, France..
    Plettemeier, D.
    Tech Univ Dresden, Wurzburger Str 35, D-01187 Dresden, Germany..
    Steller, M.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Stverak, S.
    Czech Acad Sci, Astron Inst, Prague, Czech Republic..
    Vecchio, A.
    Czech Acad Sci, Astron Inst, Prague, Czech Republic.;Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Maksimovic, M.
    Univ PSL, Sorbonne Univ, Univ Paris, Observ Paris,LESIA,CNRS, Meudon, France.;Radboud Univ Nijmegen, Dept Astrophys, Radboud Radio Lab, Nijmegen, Netherlands..
    Bale, S. D.
    Univ PSL, Sorbonne Univ, Univ Paris, Observ Paris,LESIA,CNRS, Meudon, France..
    Horbury, T. S.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.;Univ Calif Berkeley, Phys Dept, Berkeley, CA USA.;Stellar Sci, Berkeley, CA USA..
    O'Brien, H.
    Imperial Coll, Dept Phys, London SW7 2AZ, England..
    Evans, V
    Imperial Coll, Dept Phys, London SW7 2AZ, England..
    Angelini, V
    Imperial Coll, Dept Phys, London SW7 2AZ, England..
    Observations of whistler mode waves by Solar Orbiter's RPW Low Frequency Receiver (LFR): In-flight performance and first results2021In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 656, article id A17Article in journal (Refereed)
    Abstract [en]

    Context. The Radio and Plasma Waves (RPW) instrument is one of the four in situ instruments of the ESA/NASA Solar Orbiter mission, which was successfully launched on February 10, 2020. The Low Frequency Receiver (LFR) is one of its subsystems, designed to characterize the low frequency electric (quasi-DC - 10 kHz) and magnetic (similar to 1 Hz-10 kHz) fields that develop, propagate, interact, and dissipate in the solar wind plasma. Combined with observations of the particles and the DC magnetic field, LFR measurements will help to improve the understanding of the heating and acceleration processes at work during solar wind expansion.

    Aims. The capability of LFR to observe and analyze a variety of low frequency plasma waves can be demontrated by taking advantage of whistler mode wave observations made just after the near-Earth commissioning phase of Solar Orbiter. In particular, this is related to its capability of measuring the wave normal vector, the phase velocity, and the Poynting vector for determining the propagation characteristics of the waves.

    Methods. Several case studies of whistler mode waves are presented, using all possible LFR onboard digital processing products, waveforms, spectral matrices, and basic wave parameters.

    Results. Here, we show that whistler mode waves can be very properly identified and characterized, along with their Doppler-shifted frequency, based on the waveform capture as well as on the LFR onboard spectral analysis.

    Conclusions. Despite the fact that calibrations of the electric and magnetic data still require some improvement, these first whistler observations show a good overall consistency between the RPW LFR data, indicating that many science results on these waves, as well as on other plasma waves, can be obtained by Solar Orbiter in the solar wind.

    Download full text (pdf)
    FULLTEXT01
  • 35.
    Colomban, L.
    et al.
    Univ Orleans, CNRS, LPC2E, CNES, 3A Ave Rech Sci, F-45071 Orleans, France..
    Kretzschmar, M.
    Univ Orleans, CNRS, LPC2E, CNES, 3A Ave Rech Sci, F-45071 Orleans, France..
    Krasnoselkikh, V.
    Univ Orleans, CNRS, LPC2E, CNES, 3A Ave Rech Sci, F-45071 Orleans, France.;Univ Calif Berkeley, Space Sci Lab, Berkeley, CA USA..
    Agapitov, O. V.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA USA.;Natl Taras Shevchenko Univ Kyiv, Astron & Space Phys Dept, Kiev, Ukraine..
    Froment, C.
    Univ Orleans, CNRS, LPC2E, CNES, 3A Ave Rech Sci, F-45071 Orleans, France..
    Maksimovic, M.
    Univ Paris, Sorbonne Univ, Univ PSL, CNRS,LESIA,Observ Paris, Meudon, France..
    Berthomier, M.
    Univ Paris Saclay, Sorbonne Univ, Ecole Polytech, Observ Paris,LPP,CNRS, Paris, France..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Bale, S.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA USA.;Univ Calif Berkeley, Phys Dept, Berkeley, CA USA..
    Quantifying the diffusion of suprathermal electrons by whistler waves between 0.2 and 1 AU with Solar Orbiter and Parker Solar Probe2024In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 684, article id A143Article in journal (Refereed)
    Abstract [en]

    Context. The evolution of the solar wind electron distribution function with heliocentric distance exhibits different features that are still unexplained, in particular, the fast decrease in the electron heat flux and the increase in the Strahl pitch angle width. Wave-particle interactions between electrons and whistler waves are often proposed to explain these phenomena.

    Aims. We aim to quantify the effect of whistler waves on suprathermal electrons as a function of heliocentric distance.

    Methods. We first performed a statistical analysis of whistler waves (occurrence and properties) observed by Solar Orbiter and Parker Solar Probe between 0.2 and 1 AU. The wave characteristics were then used to compute the diffusion coefficients for solar wind suprathermal electrons in the framework of quasi-linear theory. These coefficients were integrated to deduce the overall effect of whistler waves on electrons along their propagation.

    Results. About 110 000 whistler wave packets were detected and characterized in the plasma frame, including their direction of propagation with respect to the background magnetic field and their radial direction of propagation. Most waves are aligned with the magnetic field and only ∼0.5% of them have a propagation angle greater than 45°. Beyond 0.3 AU, it is almost exclusively quasi-parallel waves propagating anti-sunward (some of them are found sunward but are within switchbacks with a change of sign of the radial component of the background magnetic) that are observed. Thus, these waves are found to be Strahl-aligned and not counter-streaming. At 0.2 AU, we find both Strahl-aligned and counter-streaming quasi-parallel whistler waves.

    Conclusions. Beyond 0.3 AU, the integrated diffusion coefficients show that the observed waves are sufficient to explain the measured Strahl pitch angle evolution and effective in isotropizing the halo. Strahl diffusion is mainly attributed to whistler waves with a propagation angle of θ ∈ [15.45]°, although their origin has not yet been fully determined. Near 0.2 AU, counter-streaming whistler waves are able to diffuse the Strahl electrons more efficiently than the Strahl-aligned waves by two orders of magnitude.

    Download full text (pdf)
    fulltext
  • 36.
    Cozzani, G.
    et al.
    Univ Helsinki, Dept Phys, Helsinki, Finland..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Direct Observations of Electron Firehose Fluctuations in the Magnetic Reconnection Outflow2023In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 128, no 5, article id e2022JA031128Article in journal (Refereed)
    Abstract [en]

    Electron temperature anisotropy-driven instabilities such as the electron firehose instability (EFI) are especially significant in space collisionless plasmas, where collisions are so scarce that wave-particle interactions are the leading mechanisms in the isotropization of the distribution function and energy transfer. Observational statistical studies provided convincing evidence in favor of the EFI constraining the electron distribution function and limiting the electron temperature anisotropy. Magnetic reconnection is characterized by regions of enhanced temperature anisotropy that could drive instabilities-including the electron firehose instability-affecting the particle dynamics and the energy conversion. However, in situ observations of the fluctuations generated by the EFI are still lacking and the interplay between magnetic reconnection and EFI is still largely unknown. In this study, we use high-resolution in situ measurements by the Magnetospheric Multiscale spacecraft to identify and investigate EFI fluctuations in the magnetic reconnection exhaust in the Earth's magnetotail. We find that the wave properties of the observed fluctuations largely agree with theoretical predictions of the non-propagating EF mode. These findings are further supported by comparison with the linear kinetic dispersion relation. Our results demonstrate that the magnetic reconnection outflow can be the seedbed of EFI and provide the first direct in situ observations of EFI-generated fluctuations.

    Download full text (pdf)
    fulltext
  • 37.
    Cozzani, Giulia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Egedal, J.
    Univ Wisconsin, Dept Phys, Madison, WI 53706 USA..
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, A.
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Space & Plasma Phys, S-11428 Stockholm, Sweden..
    Alexandrova, A.
    Univ Paris Saclay, Sorbonne Univ, Lab Phys Plasmas, CNRS,Observ Paris,Ecole Polytech,Inst Polytech Pa, F-91128 Palaiseau, France..
    Le Contel, O.
    Univ Paris Saclay, Sorbonne Univ, Lab Phys Plasmas, CNRS,Observ Paris,Ecole Polytech,Inst Polytech Pa, F-91128 Palaiseau, France..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria..
    Fuselier, S. A.
    Southwest Res Inst, San Antonio, TX 78238 USA.;Univ Texas San Antonio, San Antonio, TX 78249 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Structure of a Perturbed Magnetic Reconnection Electron Diffusion Region in the Earth's Magnetotail2021In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 127, no 21, article id 215101Article in journal (Refereed)
    Abstract [en]

    We report in situ observations of an electron diffusion region (EDR) and adjacent separatrix region in the Earth's magnetotail. We observe significant magnetic field oscillations near the lower hybrid frequency which propagate perpendicularly to the reconnection plane. We also find that the strong electron-scale gradients close to the EDR exhibit significant oscillations at a similar frequency. Such oscillations are not expected for a crossing of a steady 2D EDR, and can be explained by a complex motion of the reconnection plane induced by current sheet kinking propagating in the out-of-reconnection-plane direction. Thus, all three spatial dimensions have to be taken into account to explain the observed perturbed EDR crossing. These results shed light on the interplay between magnetic reconnection and current sheet drift instabilities in electron-scale current sheets and highlight the need for adopting a 3D description of the EDR, going beyond the two-dimensional and steady-state conception of reconnection.

  • 38.
    Cozzani, Giulia
    et al.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, Lab Phys Plasmas,CNRS,Ecole Polytech, F-91128 Palaiseau, France;Univ Pisa, Dipartimento Fis E Fermi, I-56127 Pisa, Italy.
    Retino, A.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, Lab Phys Plasmas,CNRS,Ecole Polytech, F-91128 Palaiseau, France.
    Califano, F.
    Univ Pisa, Dipartimento Fis E Fermi, I-56127 Pisa, Italy.
    Alexandrova, A.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, Lab Phys Plasmas,CNRS,Ecole Polytech, F-91128 Palaiseau, France.
    Contel, O. Le
    Univ Paris Sud, Sorbonne Univ, Observ Paris, Lab Phys Plasmas,CNRS,Ecole Polytech, F-91128 Palaiseau, France.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Fu, H. S.
    Beihang Univ, Sch Space & Environm, Beijing 100083, Peoples R China.
    Catapano, F.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, Lab Phys Plasmas,CNRS,Ecole Polytech, F-91128 Palaiseau, France;Univ Calabria, Dipartimento Fis, I-87036 Arcavacata Di Rende, CS, Italy.
    Breuillard, H.
    Univ Paris Sud, Sorbonne Univ, Observ Paris, Lab Phys Plasmas,CNRS,Ecole Polytech, F-91128 Palaiseau, France;Univ Orleans, UMR 7328, CNRS, Lab Phys & Chim Environm & Espace, F-45071 Orleans, France.
    Ahmadi, N.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Lindqvist, P-A
    KTH Royal Inst Technol, SE-10044 Stockholm, Sweden.
    Ergun, R. E.
    Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.
    Torbert, R. B.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Russell, C. T.
    Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA.
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria.
    Fuseher, S.
    Southwest Res Inst, San Antonio, TX 78238 USA;Univ Texas San Antonio, San Antonio, TX 78238 USA.
    Mauk, B. H.
    Johns Hopkins Univ, Appl Phys Lab, Johns Hopkins Rd, Laurel, MD 20723 USA.
    Moore, T.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX 78238 USA.
    In situ spacecraft observations of a structured electron diffusion region during magnetopause reconnection2019In: Physical review. E, ISSN 2470-0045, E-ISSN 2470-0053, Vol. 99, no 4, article id 043204Article in journal (Refereed)
    Abstract [en]

    The electron diffusion region (EDR) is the region where magnetic reconnection is initiated and electrons are energized. Because of experimental difficulties, the structure of the EDR is still poorly understood. A key question is whether the EDR has a homogeneous or patchy structure. Here we report Magnetospheric Multiscale (MMS) spacecraft observations providing evidence of inhomogeneous current densities and energy conversion over a few electron inertial lengths within an EDR at the terrestrial magnetopause, suggesting that the EDR can be rather structured. These inhomogenenities are revealed through multipoint measurements because the spacecraft separation is comparable to a few electron inertial lengths, allowing the entire MMS tetrahedron to be within the EDR most of the time. These observations are consistent with recent high-resolution and low-noise kinetic simulations.

  • 39.
    Dai, Lei
    et al.
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Wang, Chi
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Cai, Zhiming
    Chinese Acad Sci, Innovat Acad Microsatellites, Shanghai, Peoples R China..
    Gonzalez, Walter
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China.;Natl Inst Space Res INPE, Sao Jose Dos Campos, Brazil..
    Hesse, Michael
    Univ Bergen, Dept Phys & Technol, Bergen, Norway.;Southwest Res Inst, Space Sci & Engn Div, San Antonio, TX USA..
    Escoubet, Philippe
    European Space Agcy ESA, European Space Res & Technol Ctr, Noordwijk, Netherlands..
    Phan, Tai
    Vasyliunas, Vytenis
    Max Planck Inst Solar Syst Res, Gottingen, Germany..
    Lu, Quanming
    Univ Sci & Technol China, Dept Geophys & Planetary Sci, Hefei, Peoples R China..
    Li, Lei
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Kong, Linggao
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Dunlopla, Malcolm
    Rutherford Appleton Lab, Sci & Technol Facil Council STFC, Didcot, Oxon, England.;Beihang Univ, Sch Space & Environm, Beijing, Peoples R China..
    Nakamura, Rumi
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    He, Jianshen
    Beijing Univ, Beijing, Peoples R China..
    Fu, Huishan
    Beihang Univ, Sch Space & Environm, Beijing, Peoples R China..
    Zhou, Meng
    Nanchang Univ, Inst Space Sci & Technol, Nanchang, Jiangxi, Peoples R China..
    Huang, Shiyong
    Wuhan Univ, Sch Elect & Informat, Wuhan, Peoples R China..
    Wang, Rongsheng
    Univ Sci & Technol China, Dept Geophys & Planetary Sci, Hefei, Peoples R China..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel
    Swedish Inst Space Phys, Uppsala, Sweden..
    Retino, Alessandro
    Ecole Polytech, Lab Phys Plasmas LPP, Palaiseau, France..
    Zelenyi, Lev
    Russian Acad Sci, Space Res Inst, Moscow, Russia..
    Grigorenko, Elena E.
    Russian Acad Sci, Space Res Inst, Moscow, Russia..
    Runov, Andrei
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Angelopoulos, Vassilis
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Kepko, Larry
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Hwang, Kyoung-Joo
    Southwest Res Inst, Space Sci & Engn Div, San Antonio, TX USA..
    Zhang, Yongcun
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    AME: A Cross-Scale Constellation of CubeSats to Explore Magnetic Reconnection in the Solar-Terrestrial Relation2020In: Frontiers in Physics, E-ISSN 2296-424X, Vol. 8, article id 89Article in journal (Refereed)
    Abstract [en]

    A major subset of solar-terrestrial relations, responsible, in particular, for the driver of space weather phenomena, is the interaction between the Earth's magnetosphere and the solar wind. As one of the most important modes of the solar-wind-magnetosphere interaction, magnetic reconnection regulates the energy transport and energy release in the solar-terrestrial relation. In situ measurements in the near-Earth space are crucial for understanding magnetic reconnection. Past and existing spacecraft constellation missions mainly focus on the measurement of reconnection on plasma kinetic-scales. Resolving the macro-scale and cross-scale aspects of magnetic reconnection is necessary for accurate assessment and predictions of its role in the context of space weather. Here, we propose the AME (self-Adaptive Magnetic reconnection Explorer) mission consisting of a cross-scale constellation of 12+ CubeSats and one mother satellite. Each CubeSat is equipped with instruments to measure magnetic fields and thermal plasma particles. With multiple CubeSats, the AME constellation is intended to make simultaneous measurements at multiple scales, capable of exploring cross-scale plasma processes ranging from kinetic scale to macro scale.

    Download full text (pdf)
    FULLTEXT01
  • 40.
    Dimmock, Andrew P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Gedalin, M.
    Ben Gurion Univ Negev, Dept Phys, Beer Sheva, Israel..
    Lalti, Ahmad
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics.
    Trotta, D.
    Imperial Coll London, London, England..
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Johlander, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Swedish Def Res Agcy, Stockholm, Sweden..
    Vainio, R.
    Univ Turku, Turku, Finland..
    Blanco-Cano, X.
    Univ Nacl Autonoma Mexico, Dept Ciencias Espaciales, Inst Geofis, Ciudad De Mexico, Mexico..
    Kajdic, P.
    Univ Nacl Autonoma Mexico, Dept Ciencias Espaciales, Inst Geofis, Ciudad De Mexico, Mexico..
    Owen, C. J.
    UCL, Mullard Space Sci Lab, London, England..
    Wimmer-Schweingruber, R. F.
    Univ Kiel, Inst Expt & Appl Phys, D-24118 Kiel, Germany..
    Backstreaming ions at a high Mach number interplanetary shock: Solar Orbiter measurements during the nominal mission phase2023In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 679, article id A106Article in journal (Refereed)
    Abstract [en]

    Context: Solar Orbiter, a mission developed by the European Space Agency, explores in situ plasma across the inner heliosphere while providing remote-sensing observations of the Sun. The mission aims to study the solar wind, but also transient structures such as interplanetary coronal mass ejections and stream interaction regions. These structures often contain a leading shock wave that can differ from other plasma shock waves, such as those around planets. Importantly, the Mach number of these interplanetary shocks is typically low (1-3) compared to planetary bow shocks and most astrophysical shocks. However, our shock survey revealed that on 30 October 2021, Solar Orbiter measured a shock with an Alfven Mach number above 6, which can be considered high in this context.

    Aims: Our study examines particle observations for the 30 October 2021 shock. The particles provide clear evidence of ion reflection up to several minutes upstream of the shock. Additionally, the magnetic and electric field observations contain complex electromagnetic structures near the shock, and we aim to investigate how they are connected to ion dynamics. The main goal of this study is to advance our understanding of the complex coupling between particles and the shock structure in high Mach number regimes of interplanetary shocks.

    Methods: We used observations of magnetic and electric fields, probe-spacecraft potential, and thermal and energetic particles to characterize the structure of the shock front and particle dynamics. Furthermore, ion velocity distribution functions were used to study reflected ions and their coupling to the shock. To determine shock parameters and study waves, we used several methods, including cold plasma theory, singular-value decomposition, minimum variance analysis, and shock Rankine-Hugoniot relations. To support the analysis and interpretation of the experimental data, test-particle analysis, and hybrid particle in-cell simulations were used.

    Results: The ion velocity distribution functions show clear evidence of particle reflection in the form of backstreaming ions several minutes upstream. The shock structure has complex features at the ramp and whistler precursors. The backstreaming ions may be modulated by the complex shock structure, and the whistler waves are likely driven by gyrating ions in the foot. Supra-thermal ions up to 20 keV were observed, but shock-accelerated particles with energies above this were not.

    Download full text (pdf)
    fulltext
  • 41.
    Dimmock, Andrew P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Russell, Christopher T.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA 90095 USA.
    Sagdeev, Roald Z.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA.
    Krasnoselskikh, Vladimir
    Univ Orleans, CNRS, LPC2E, Orleans, France;Univ Calif Berkeley, Space Sci Lab, 7 Gauss Way, Berkeley, CA 94720 USA.
    Walker, Simon N.
    Univ Sheffield, Dept Automat Control & Syst Engn, Sheffield, S Yorkshire, England.
    Carr, Christopher
    Imperial Coll London, London SW7 2AZ, England.
    Dandouras, Iannis
    Univ Toulouse, IRAP, CNRS, UPS,CNES, Toulouse, France.
    Escoubet, C. Philippe
    European Space Agcy, European Space Res & Technol Ctr ESA ESTEC, Noordwijk, Netherlands.
    Ganushkina, Natalia
    Finnish Meteorol Inst, Helsinki, Finland;Univ Michigan, Ann Arbor, MI 48109 USA.
    Gedalin, Michael
    Ben Gurion Univ Negev, Dept Phys, Beer Sheva, Israel.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Aryan, Homayon
    Univ Sheffield, Dept Automat Control & Syst Engn, Sheffield, S Yorkshire, England;NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Pulkkinen, Tuija, I
    Univ Michigan, Ann Arbor, MI 48109 USA;Aalto Univ, Sch Elect Engn, Dept Elect & Nanoengn, Espoo, Finland.
    Balikhin, Michael A.
    Univ Sheffield, Dept Automat Control & Syst Engn, Sheffield, S Yorkshire, England.
    Direct evidence of nonstationary collisionless shocks in space plasmas2019In: Science Advances, E-ISSN 2375-2548, Vol. 5, no 2, article id eaau9926Article in journal (Refereed)
    Abstract [en]

    Collisionless shocks are ubiquitous throughout the universe: around stars, supernova remnants, active galactic nuclei, binary systems, comets, and planets. Key information is carried by electromagnetic emissions from particles accelerated by high Mach number collisionless shocks. These shocks are intrinsically nonstationary, and the characteristic physical scales responsible for particle acceleration remain unknown. Quantifying these scales is crucial, as it affects the fundamental process of redistributing upstream plasma kinetic energy into other degrees of freedom-particularly electron thermalization. Direct in situ measurements of nonstationary shock dynamics have not been reported. Thus, the model that best describes this process has remained unknown. Here, we present direct evidence demonstrating that the transition to nonstationarity is associated with electron-scale field structures inside the shock ramp.

    Download full text (pdf)
    FULLTEXT01
  • 42.
    Dimmock, Andrew P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Yordanova, Emiliya
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Blanco-Cano, X.
    Univ Nacl Autonoma Mexico, Inst Geofis, Dept Ciencias Espaciales, Ciudad Univ, Ciudad De Mexico, Mexico..
    KajdiC, P.
    Univ Nacl Autonoma Mexico, Inst Geofis, Dept Ciencias Espaciales, Ciudad Univ, Ciudad De Mexico, Mexico..
    Karlsson, T.
    KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Div Space & Plasma Phys, Stockholm, Sweden..
    Fedorov, A.
    IRAP UPS CNRS, Toulouse, France..
    Owen, C. J.
    UCL, Mullard Space Sci Lab, London, England..
    Werner, Elisabeth
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Johlander, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Mirror Mode Storms Observed by Solar Orbiter2022In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 127, no 11, article id e2022JA030754Article in journal (Refereed)
    Abstract [en]

    Mirror modes (MMs) are ubiquitous in space plasma and grow from pressure anisotropy. Together with other instabilities, they play a fundamental role in constraining the free energy contained in the plasma. This study focuses on MMs observed in the solar wind by Solar Orbiter (SolO) for heliocentric distances between 0.5 and 1 AU. Typically, MMs have timescales from several to tens of seconds and are considered quasi-MHD structures. In the solar wind, they also generally appear as isolated structures. However, in certain conditions, prolonged and bursty trains of higher frequency MMs are measured, which have been labeled previously as MM storms. At present, only a handful of existing studies have focused on MM storms, meaning that many open questions remain. In this study, SolO has been used to investigate several key aspects of MM storms: their dependence on heliocentric distance, association with local plasma properties, temporal/spatial scale, amplitude, and connections with larger-scale solar wind transients. The main results are that MM storms often approach local ion scales and can no longer be treated as quasi-magnetohydrodynamic, thus breaking the commonly used long-wavelength assumption. They are typically observed close to current sheets and downstream of interplanetary shocks. The events were observed during slow solar wind speeds and there was a tendency for higher occurrence closer to the Sun. The occurrence is low, so they do not play a fundamental role in regulating ambient solar wind but may play a larger role inside transients.

    Download full text (pdf)
    fulltext
  • 43.
    Divin, A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Markidis, S.
    Lapenta, G.
    Evolution of the lower hybrid drift instability at reconnection jet front2015In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 120, no 4, p. 2675-2690Article in journal (Refereed)
    Abstract [en]

    We investigate current-driven modes developing at jet fronts during collisionless reconnection. Initial evolution of the reconnection is simulated using conventional 2-D setup starting from the Harris equilibrium. Three-dimensional PIC calculations are implemented at later stages, when fronts are fully formed. Intense currents and enhanced wave activity are generated at the fronts because of the interaction of the fast flow plasma and denser ambient current sheet plasma. The study reveals that the lower hybrid drift instability develops quickly in the 3-D simulation. The instability produces strong localized perpendicular electric fields, which are several times larger than the convective electric field at the front, in agreement with Time History of Events and Macroscale Interactions during Substorms observations. The instability generates waves, which escape the front edge and propagate into the undisturbed plasma ahead of the front. The parallel electron pressure is substantially larger in the 3-D simulation compared to that of the 2-D. In a time similar to Omega(-1)(ci), the instability forms a layer, which contains a mixture of the jet plasma and current sheet plasma. The results confirm that the lower hybrid drift instability is important for the front evolution and electron energization.

  • 44.
    Divin, Andrey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lower hybrid drift instability at a dipolarization front2015In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 120, no 2, p. 1124-1132Article in journal (Refereed)
    Abstract [en]

    We present observations of a reconnection jet front detected by the Cluster satellites in the magnetotail of Earth, which are commonly referred to as dipolarization fronts. We investigate in detail electric field structures observed at the front which have frequency in the lower hybrid range and amplitudes reaching 40mV/m. We determine the frequency and phase velocity of these structures in the reference frame of the front and identify them as a manifestation of the lower hybrid drift instability (LHDI) excited at the sharp density gradient at the front. The LHDI is observed in the nonlinear stage of its evolution as the electrostatic potential of the structures is comparable to approximate to 10% of the electron temperature. The front appears to be a coherent structure on ion and MHD scales, suggesting existence of a dynamic equilibrium between excitation of the LHDI and recovery of the steep density gradient at the front.

  • 45.
    Divin, Andrey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Toledo-Redondo, S.
    European Space Agcy, ESAC, Sci Directorate, Madrid, Spain..
    Markidis, S.
    KTH Royal Inst Technol, Dept Computat Sci & Technol, Stockholm, Sweden..
    Lapenta, G.
    Katholieke Univ Leuven, Ctr Math Plasma Astrophys, Dept Math, Leuven, Belgium..
    Three-scale structure of diffusion region in the presence of cold ions2016In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 121, no 12, p. 12001-12013Article in journal (Refereed)
    Abstract [en]

    Kinetic simulations and spacecraft observations typically display the two-scale structure of collisionless diffusion region (DR), with electron and ion demagnetization scales governing the spatial extent of the DR. Recent in situ observations of the nightside magnetosphere, as well as investigation of magnetic reconnection events at the Earth's magnetopause, discovered the presence of a population of cold (tens of eV) ions of ionospheric origin. We present two-dimensional particle-in-cell simulations of collisionless magnetic reconnection in multicomponent plasma with ions consisting of hot and cold populations. We show that a new cold ion diffusion region scale is introduced in between that of hot ions and electrons. Demagnetization scale of cold ion population is several times (similar to 4-8) larger than the initial cold ion gyroradius. Cold ions are accelerated and thermalized during magnetic reconnection and form ion beams moving with velocities close to the Alfven velocity.

  • 46.
    Duan, Suping
    et al.
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Dai, Lei
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Wang, Chi
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    He, Zhaohai
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Cai, Chunlin
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Zhang, Y. C.
    Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China..
    Dandouras, I.
    Univ Toulouse, UPS OMP, IRAP, Toulouse, France.;CNRS, IRAP, Toulouse, France..
    Reme, H.
    Univ Toulouse, UPS OMP, IRAP, Toulouse, France.;CNRS, IRAP, Toulouse, France..
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Oxygen Ions O+ Energized by Kinetic Alfven Eigenmode During Dipolarizations of Intense Substorms2017In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 11, p. 11256-11273Article in journal (Refereed)
    Abstract [en]

    Singly charged oxygen ions, O+, energized by kinetic Alfven wave eigenmode (KAWE) in the plasma sheet boundary layer during dipolarizations of two intense substorms, 10: 07 UT on 31 August 2004 and 18: 24 UT on 14 September 2004, are investigated by Cluster spacecraft in the magnetotail. It is found that after the beginning of the expansion phase of substorms, O+ ions are clearly energized in the direction perpendicular to the magnetic field with energy larger than 1 keV in the near-Earth plasma sheet during magnetic dipolarizations. The pitch angle distribution of these energetic O+ ions is significantly different from that of O+ ions with energy less than 1 keV before substorm onset that is in the quasi-parallel direction along the magnetic field. The KAWE with the large perpendicular unipolar electric field, E-z similar to -20 mV/m, significantly accelerates O+ ions in the direction perpendicular to the background magnetic field. We present good evidences that O+ ion origin from the ionosphere along the magnetic field line in the northward lobe can be accelerated in the perpendicular direction during substorm dipolarizations. The change of the move direction of O+ ions is useful for O+ transferring from the lobe into the central plasma sheet in the magnetotail. Thus, KAWE can play an important role in O+ ion transfer process from the lobe into the plasma sheet during intense substorms.

  • 47.
    Eastwood, J. P.
    et al.
    Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England..
    Phan, T. D.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Cassak, P. A.
    W Virginia Univ, Dept Phys & Astron, Morgantown, WV 26506 USA..
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Haggerty, C.
    Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Malakit, K.
    Mahidol Univ, Dept Phys, Bangkok 10700, Thailand..
    Shay, M. A.
    Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Mistry, R.
    Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England..
    Oieroset, M.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Slavin, J. A.
    Univ Michigan, Dept Climate & Space Sci & Engn, Ann Arbor, MI 48109 USA..
    Argall, M. R.
    Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA..
    Avanov, L. A.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Burch, J. L.
    SW Res Inst, San Antonio, TX USA..
    Chen, L. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Dorelli, J. C.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Ergun, R. E.
    Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Lavraud, B.
    Univ Toulouse, Inst Rech Astrophys & Planetol, Toulouse, France.;CNRS, UMR 5277, Toulouse, France..
    Lindqvist, P. A.
    Royal Inst Technol, Sch Elect Engn, Stockholm, Sweden..
    Moore, T. E.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Paterson, W.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Pollock, C.
    Denali Sci, Healy, AK USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Torbert, R. B.
    Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA.;SW Res Inst, San Antonio, TX USA..
    Wang, S.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Ion-scale secondary flux ropes generated by magnetopause reconnection as resolved by MMS2016In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 10, p. 4716-4724Article in journal (Refereed)
    Abstract [en]

    New Magnetospheric Multiscale (MMS) observations of small-scale (similar to 7 ion inertial length radius) flux transfer events (FTEs) at the dayside magnetopause are reported. The 10 km MMS tetrahedron size enables their structure and properties to be calculated using a variety of multispacecraft techniques, allowing them to be identified as flux ropes, whose flux content is small (similar to 22 kWb). The current density, calculated using plasma and magnetic field measurements independently, is found to be filamentary. Intercomparison of the plasma moments with electric and magnetic field measurements reveals structured non-frozen-in ion behavior. The data are further compared with a particle-in-cell simulation. It is concluded that these small-scale flux ropes, which are not seen to be growing, represent a distinct class of FTE which is generated on the magnetopause by secondary reconnection.

    Download full text (pdf)
    fulltext
  • 48.
    Ergun, R. E.
    et al.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Goodrich, K. A.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Wilder, F. D.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Holmes, J. C.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Stawarz, J. E.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Eriksson, S.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Sturner, A. P.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA..
    Malaspina, D. M.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA..
    Usanova, M. E.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA..
    Torbert, R. B.
    Univ New Hampshire, Durham, NH 03824 USA.;Southwest Res Inst, San Antonio, TX 78238 USA..
    Lindqvist, P. -A
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX 78238 USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Hesse, M.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Chen, L. J.
    Univ Maryland, College Pk, MD 20742 USA..
    Lapenta, G.
    Leuven Univ, Leuven, Belgium..
    Goldman, M. V.
    Univ Colorado, Dept Phys, Boulder, CO 80303 USA..
    Newman, D. L.
    Univ Colorado, Dept Phys, Boulder, CO 80303 USA..
    Schwartz, S. J.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80303 USA.;Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England..
    Eastwood, J. P.
    Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England..
    Phan, T. D.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Mozer, F. S.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Drake, J.
    Univ Maryland, College Pk, MD 20742 USA..
    Shay, M. A.
    Univ Delaware, Newark, DE 19716 USA..
    Cassak, P. A.
    W Virginia Univ, Morgantown, WV 26506 USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria..
    Marklund, G.
    KTH Royal Inst Technol, Stockholm, Sweden..
    Magnetospheric Multiscale Satellites Observations of Parallel Electric Fields Associated with Magnetic Reconnection2016In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 116, no 23, article id 235102Article in journal (Refereed)
    Abstract [en]

    We report observations from the Magnetospheric Multiscale satellites of parallel electric fields (E-vertical bar vertical bar) associated with magnetic reconnection in the subsolar region of the Earth's magnetopause. E-vertical bar vertical bar events near the electron diffusion region have amplitudes on the order of 100 mV/m, which are significantly larger than those predicted for an antiparallel reconnection electric field. This Letter addresses specific types of E-vertical bar vertical bar events, which appear as large-amplitude, near unipolar spikes that are associated with tangled, reconnected magnetic fields. These E-vertical bar vertical bar events are primarily in or near a current layer near the separatrix and are interpreted to be double layers that may be responsible for secondary reconnection in tangled magnetic fields or flux ropes. These results are telling of the three-dimensional nature of magnetopause reconnection and indicate that magnetopause reconnection may be often patchy and/or drive turbulence along the separatrix that results in flux ropes and/or tangled magnetic fields.

  • 49.
    Ergun, R. E.
    et al.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Holmes, J. C.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Goodrich, K. A.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Wilder, F. D.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Stawarz, J. E.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Eriksson, S.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Newman, D. L.
    Univ Colorado, Dept Phys, Boulder, CO 80309 USA..
    Schwartz, S. J.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA.;Imperial Coll London, Blackett Lab, London, England..
    Goldman, M. V.
    Univ Colorado, Dept Phys, Boulder, CO 80309 USA..
    Sturner, A. P.
    Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA.;Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Malaspina, D. M.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Usanova, M. E.
    Univ Colorado, Lab Atmospher & Space Sci, Boulder, CO 80309 USA..
    Torbert, R. B.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA.;Southwest Res Inst, San Antonio, TX USA..
    Argall, M.
    Univ New Hampshire, Dept Phys, Durham, NH 03824 USA..
    Lindqvist, P-A
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA..
    Strangeway, R. J.
    Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA..
    Russell, C. T.
    Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA..
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Dorelli, J. J. C.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Avanov, L.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Hesse, M.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Chen, L. J.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Lavraud, B.
    Univ Toulouse, Inst Rech Astrophys & Planetol, Toulouse, France.;CNRS, Toulouse, France..
    Le Contel, O.
    Lab Phys Plasmas, Palaiseau, France..
    Retino, A.
    Lab Phys Plasmas, Palaiseau, France..
    Phan, T. D.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Eastwood, J. P.
    Imperial Coll London, Blackett Lab, London, England..
    Oieroset, M.
    Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA..
    Drake, J.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA..
    Shay, M. A.
    Univ Delaware, Dept Phys & Astron, Bartol Res Inst, Newark, DE 19716 USA..
    Cassak, P. A.
    West Virginia Univ, Dept Phys & Astron, Morgantown, WV USA..
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, Graz, Austria..
    Zhou, M.
    Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA USA..
    Ashour-Abdalla, M.
    Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA USA..
    Andre, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Magnetospheric Multiscale observations of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the magnetopause2016In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 11, p. 5626-5634Article in journal (Refereed)
    Abstract [en]

    We report observations from the Magnetospheric Multiscale satellites of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the Earth's magnetopause. The observed waves have parallel electric fields (E-||) with amplitudes on the order of 100mV/m and display nonlinear characteristics that suggest a possible net E-||. These waves are observed within the ion diffusion region and adjacent to (within several electron skin depths) the electron diffusion region. They are in or near the magnetosphere side current layer. Simulation results support that the strong electrostatic linear and nonlinear wave activities appear to be driven by a two stream instability, which is a consequence of mixing cold (<10eV) plasma in the magnetosphere with warm (similar to 100eV) plasma from the magnetosheath on a freshly reconnected magnetic field line. The frequent observation of these waves suggests that cold plasma is often present near the magnetopause.

  • 50.
    Eriksson, Elin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. KTH Royal Inst Technol, Sch Elect Engn & Comp Sci, Space & Plasma Phys, Stockholm, Sweden.
    Alm, Love
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Graham, Daniel B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Electron acceleration in a magnetotail reconnection outflow region using Magnetospheric MultiScale data2020In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 47, no 1, article id e2019GL085080Article in journal (Refereed)
    Download full text (pdf)
    fulltext
123456 1 - 50 of 298
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf