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Svenningsson, I., Yordanova, E., Khotyaintsev, Y. V., André, M., Cozzani, G. & Steinvall, K. (2024). Whistler Waves in the Quasi-Parallel and Quasi-Perpendicular Magnetosheath. Journal of Geophysical Research - Space Physics, 129(6), Article ID e2024JA032661.
Open this publication in new window or tab >>Whistler Waves in the Quasi-Parallel and Quasi-Perpendicular Magnetosheath
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2024 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 129, no 6, article id e2024JA032661Article in journal (Refereed) Published
Abstract [en]

In the Earth's magnetosheath (MSH), several processes contribute to energy dissipation and plasma heating, one of which is wave-particle interactions between whistler waves and electrons. However, the overall impact of whistlers on electron dynamics in the MSH remains to be quantified. We analyze 18 hr of burst-mode measurements from the Magnetospheric Multiscale (MMS) mission, including data from the unbiased magnetosheath campaign during February-March 2023. We present a statistical study of 34,409 whistler waves found using automatic detection. We compare wave occurrence in the different MSH geometries and find three times higher occurrence in the quasi-perpendicular MSH compared to the quasi-parallel case. We also study the wave properties and find that the waves propagate quasi-parallel to the background magnetic field, have a median frequency of 0.2 times the electron cyclotron frequency, median amplitude of 0.03-0.06 nT (30-60 pT), and median duration of a few tens of wave periods. The whistler waves are preferentially observed in local magnetic dips and density peaks and are not associated with an increased temperature anisotropy. Also, almost no whistlers are observed in regions with parallel electron plasma beta lower than 0.1. Importantly, when estimating pitch-angle diffusion times we find that the whistler waves cause significant pitch-angle scattering of electrons in the MSH. Whistlers exist throughout the magnetosheath with higher occurrence in the quasi-perpendicular geometry and in local magnetic field dips Whistlers are observed in regions with electron beta above 0.1 and are not correlated with electron temperature anisotropy Whistlers cause significant pitch-angle scattering of magnetosheath electrons

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2024
Keywords
magnetosheath, whistler waves, pitch-angle diffusion, cyclotron resonance
National Category
Fusion, Plasma and Space Physics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-534073 (URN)10.1029/2024JA032661 (DOI)001247258800001 ()
Funder
Swedish Research CouncilSwedish National Space Board, 145/18Swedish National Space Board, 192/20
Available from: 2024-07-03 Created: 2024-07-03 Last updated: 2024-07-03Bibliographically approved
Cozzani, G., Khotyaintsev, Y. V., Graham, D. B. & André, M. (2023). Direct Observations of Electron Firehose Fluctuations in the Magnetic Reconnection Outflow. Journal of Geophysical Research - Space Physics, 128(5), Article ID e2022JA031128.
Open this publication in new window or tab >>Direct Observations of Electron Firehose Fluctuations in the Magnetic Reconnection Outflow
2023 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 128, no 5, article id e2022JA031128Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2023
Keywords
plasma instabilities, electron firehose instability, magnetic reconnection, collisionless plasmas, spacecraft observations
National Category
Astronomy, Astrophysics and Cosmology Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-505236 (URN)10.1029/2022JA031128 (DOI)001000427100001 ()
Funder
Swedish National Space Board, 128/17
Available from: 2023-06-26 Created: 2023-06-26 Last updated: 2023-06-26Bibliographically approved
Boldu O Farrill Treviño, J. J., Graham, D. B., Khotyaintsev, Y. V., Morooka, M., André, M., Dimmock, A. P., . . . Maksimovic, M. (2023). Ion-acoustic waves associated with interplanetary shocks.
Open this publication in new window or tab >>Ion-acoustic waves associated with interplanetary shocks
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2023 (English)In: Article in journal (Other academic) Submitted
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-516736 (URN)
Available from: 2023-11-28 Created: 2023-11-28 Last updated: 2023-11-28
Graham, D. B., Khotyaintsev, Y. V. & André, M. (2023). Langmuir and Upper Hybrid Waves in Earth's Magnetotail. Journal of Geophysical Research - Space Physics, 128(10), Article ID e2023JA031900.
Open this publication in new window or tab >>Langmuir and Upper Hybrid Waves in Earth's Magnetotail
2023 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 128, no 10, article id e2023JA031900Article in journal (Refereed) Published
Abstract [en]

Waves at the electron plasma frequency are found throughout the heliosphere. They provide indicators of unstable electron distributions, are routinely used to estimate the local electron number density, and can lead to radio wave emission at the plasma frequency and its harmonics. Although they have been studied extensively in various solar and heliospheric plasma regions, there is a lack of statistical studies of plasma frequency waves in Earth's magnetotail. Here, the occurrence and properties of plasma frequency waves, namely Langmuir and upper hybrid (UH) waves, are investigated in Earth's magnetotail using the four Magnetospheric Multiscale spacecraft. In Earth's magnetotail plasma frequency waves are observed about 1% of the time. About 80% of the waves are identified as Langmuir waves, while about 20% are identified as UH waves. The waves are primarily found in the plasma sheet boundary layer. By comparing with the local electron distributions it is shown that the Langmuir waves are generated by the bump-on-tail instability, while UH waves are typically associated with broad electron beams or loss-cone-like distributions. The majority of the waves are found in close proximity to ion outflow regions associated with magnetic reconnection in the magnetotail. The waves are likely generated by plasma sheet electrons escaping along newly reconnected magnetic field lines or electron beams propagating toward the distant magnetotail.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2023
Keywords
plasma, waves, magnetotail, instabilities
National Category
Fusion, Plasma and Space Physics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-515482 (URN)10.1029/2023JA031900 (DOI)001082313500001 ()
Funder
Swedish National Space Board, 128/17Swedish National Space Board
Available from: 2023-11-06 Created: 2023-11-06 Last updated: 2023-11-06Bibliographically approved
Kramer, E., Hamrin, M., Gunell, H., Karlsson, T., Steinvall, K., Goncharov, O. & André, M. (2023). Waves in Magnetosheath Jets-Classification and the Search for Generation Mechanisms Using MMS Burst Mode Data. Journal of Geophysical Research - Space Physics, 128(7), Article ID e2023JA031621.
Open this publication in new window or tab >>Waves in Magnetosheath Jets-Classification and the Search for Generation Mechanisms Using MMS Burst Mode Data
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2023 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 128, no 7, article id e2023JA031621Article in journal (Refereed) Published
Abstract [en]

Magnetosheath jets are localized dynamic pressure enhancements in the magnetosheath. We make use of the high time resolution burst mode data of the Magnetospheric Multiscale mission for an analysis of waves in plasmas associated with three magnetosheath jets. We find both electromagnetic and electrostatic waves over the frequency range from 0 to 4 kHz that can be probed by the instruments on board the MMS spacecraft. At high frequencies we find electrostatic solitary waves, electron acoustic waves, and whistler waves. Electron acoustic waves and whistler waves show the typical properties expected from theory assuming approximations of a homogeneous plasma and linearity. In addition, 0.2 Hz waves in the magnetic field, 1 Hz electromagnetic waves, and lower hybrid waves are observed. For these waves the approximation of a homogeneous plasma does not hold anymore and the observed waves show properties from several different basic wave modes. In addition, we investigate how the various types of waves are generated. We show evidence that, the 1 Hz waves are connected to gradients in the density and magnetic field. The whistler waves are generated by a butterfly-shaped pitch-angle distribution and the electron acoustic waves by a cold electron population. The lower hybrid waves are probably generated by currents at the boundary of the jets. As for the other waves we can only speculate about the generation mechanism due to limitations of the instruments. Studying waves in jets will help to address the microphysics in jets which can help to understand the evolution of jets better.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2023
Keywords
magnetosheath, MMS, waves, Magnetosheath Jets
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-508186 (URN)10.1029/2023JA031621 (DOI)001022282200001 ()
Funder
Swedish Research Council, 2018-03623Swedish National Space Board, 108/18Swedish National Space Board, SNSA 2020-00058
Available from: 2023-07-21 Created: 2023-07-21 Last updated: 2023-07-21Bibliographically approved
Svenningsson, I., Yordanova, E., Cozzani, G., Khotyaintsev, Y. V. & André, M. (2022). Kinetic Generation of Whistler Waves in the Turbulent Magnetosheath. Geophysical Research Letters, 49(15), Article ID e2022GL099065.
Open this publication in new window or tab >>Kinetic Generation of Whistler Waves in the Turbulent Magnetosheath
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2022 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 49, no 15, article id e2022GL099065Article in journal (Refereed) Published
Abstract [en]

The Earth's magnetosheath (MSH) is governed by numerous physical processes which shape the particle velocity distributions and contribute to the heating of the plasma. Among them are whistler waves which can interact with electrons. We investigate whistler waves detected in the quasi-parallel MSH by NASA's Magnetospheric Multiscale mission. We find that the whistler waves occur even in regions that are predicted stable to wave growth by electron temperature anisotropy. Whistlers are observed in ion-scale magnetic minima and are associated with electrons having butterfly-shaped pitch-angle distributions. We investigate in detail one example and, with the support of modeling by the linear numerical dispersion solver Waves in Homogeneous, Anisotropic, Multicomponent Plasmas, we demonstrate that the butterfly distribution is unstable to the observed whistler waves. We conclude that the observed waves are generated locally. The result emphasizes the importance of considering complete 3D particle distribution functions, and not only the temperature anisotropy, when studying plasma wave instabilities.

Place, publisher, year, edition, pages
American Geophysical Union (AGU)American Geophysical Union (AGU), 2022
Keywords
quasi-parallel magnetosheath, whistler waves, electron butterfly distribution
National Category
Fusion, Plasma and Space Physics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-483756 (URN)10.1029/2022GL099065 (DOI)000841035000001 ()
Funder
Swedish Research Council, 2016-0550Swedish Research Council, 2016-05507Swedish National Space Board, 158/16Swedish National Space Board, 145/18EU, European Research Council, 682068-PRESTISSIMO
Available from: 2022-09-02 Created: 2022-09-02 Last updated: 2024-04-29Bibliographically approved
André, M. (2022). Space Physics: The Need for a Wider Perspective. Frontiers in Astronomy and Space Sciences, 9, Article ID 937742.
Open this publication in new window or tab >>Space Physics: The Need for a Wider Perspective
2022 (English)In: Frontiers in Astronomy and Space Sciences, E-ISSN 2296-987X, Vol. 9, article id 937742Article in journal (Refereed) Published
Abstract [en]

We argue that many studies in space physics would benefit from putting a detailed investigation into a wider perspective. Three examples of theoretical and observational studies are given. We argue that space physics should aim to be less of an isolated branch of science. Rather, by putting the scientific space results into a wider perspective these results will become more interesting and important than ever. We argue that diversity in a team often is favourable for work on complicated problems and helps to present the results in a wider perspective.

Place, publisher, year, edition, pages
Frontiers Media S.A.Frontiers Media SA, 2022
Keywords
diversity, dispersion surfaces, ion energization, ionospheric outflow, low-energy ions, spacecraft charging
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-481435 (URN)10.3389/fspas.2022.937742 (DOI)000820008800001 ()
Available from: 2022-08-11 Created: 2022-08-11 Last updated: 2024-01-15Bibliographically approved
Maksimovic, M., Soucek, J., Chust, T., Khotyaintsev, Y. V., Kretzschmar, M., Bonnin, X., . . . Zouganelis, I. (2021). First observations and performance of the RPW instrument on board the Solar Orbiter mission. Astronomy and Astrophysics, 656, Article ID A41.
Open this publication in new window or tab >>First observations and performance of the RPW instrument on board the Solar Orbiter mission
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2021 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 656, article id A41Article in journal (Refereed) Published
Abstract [en]

The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is designed to measure in situ magnetic and electric fields and waves from the continuum up to several hundred kHz. The RPW also observes solar and heliospheric radio emissions up to 16 MHz. It was switched on and its antennae were successfully deployed two days after the launch of Solar Orbiter on February 10, 2020. Since then, the instrument has acquired enough data to make it possible to assess its performance and the electromagnetic disturbances it experiences. In this article, we assess its scientific performance and present the first RPW observations. In particular, we focus on a statistical analysis of the first observations of interplanetary dust by the instrument's Thermal Noise Receiver. We also review the electro-magnetic disturbances that RPW suffers, especially those which potential users of the instrument data should be aware of before starting their research work.

Place, publisher, year, edition, pages
EDP SciencesEDP Sciences, 2021
Keywords
solar wind, Sun, radio radiation, general
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-464276 (URN)10.1051/0004-6361/202141271 (DOI)000730246400039 ()
Funder
Swedish National Space Board
Available from: 2022-01-17 Created: 2022-01-17 Last updated: 2024-01-15Bibliographically approved
Li, K., André, M., Eriksson, A., Wei, Y., Cui, J. & Haaland, S. (2021). High-Latitude Cold Ion Outflow Inferred From the Cluster Wake Observations in the Magnetotail Lobes and the Polar Cap Region. Frontiers in Physics, 9, Article ID 743316.
Open this publication in new window or tab >>High-Latitude Cold Ion Outflow Inferred From the Cluster Wake Observations in the Magnetotail Lobes and the Polar Cap Region
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2021 (English)In: Frontiers in Physics, E-ISSN 2296-424X, Vol. 9, article id 743316Article, review/survey (Refereed) Published
Abstract [en]

Cold ions with low (a few eV) thermal energies and also often low bulk drift energies, dominate the ion population in the Earth's magnetosphere. These ions mainly originate from the ionosphere. Here we concentrate on cold ions in the high latitude polar regions, where magnetic field lines are open and connected to the magnetotail. Outflow from the ionosphere can modify the dynamics of the magnetosphere. In-situ observations of low energy ions are challenging. In the low-density polar regions the equivalent spacecraft potential is often large compared to cold ion energies and the ions cannot reach the spacecraft. Rather, a supersonic ion flow creates an enhanced wake. The local electric field associated with this wake can be used to detect the drifting cold ions, and this wake technique can be used for statistical studies. In this paper, we review some of the key results obtained from this technique. These results help us to understand how cold ionospheric outflow varies with various conditions of solar activities and the Earth's intrinsic magnetic field.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2021
Keywords
cold ion, ionospheric outflow, polar wind, solar wind, geomagnetic field
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-521502 (URN)10.3389/fphy.2021.743316 (DOI)001050832600001 ()
Funder
Swedish National Space Board, 2020-00058
Available from: 2024-01-29 Created: 2024-01-29 Last updated: 2024-01-29Bibliographically approved
Toledo-Redondo, S., André, M., Aunai, N., Chappell, C. R., Dargent, J., Fuselier, S. A., . . . Vines, S. K. (2021). Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics. Reviews of geophysics, 59(3), Article ID e2020RG000707.
Open this publication in new window or tab >>Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics
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2021 (English)In: Reviews of geophysics, ISSN 8755-1209, E-ISSN 1944-9208, Vol. 59, no 3, article id e2020RG000707Article, review/survey (Refereed) Published
Abstract [en]

Ionospheric ions (mainly H+, He+, and O+) escape from the ionosphere and populate the Earth's magnetosphere. Their thermal energies are usually low when they first escape the ionosphere, typically a few electron volt to tens of electron volt, but they are energized in their journey through the magnetosphere. The ionospheric population is variable, and it makes significant contributions to the magnetospheric mass density in key regions where magnetic reconnection is at work. Solar wind—magnetosphere coupling occurs primarily via magnetic reconnection, a key plasma process that enables transfer of mass and energy into the near-Earth space environment. Reconnection leads to the triggering of magnetospheric storms, auroras, energetic particle precipitation and a host of other magnetospheric phenomena. Several works in the last decades have attempted to statistically quantify the amount of ionospheric plasma supplied to the magnetosphere, including the two key regions where magnetic reconnection occurs: the dayside magnetopause and the magnetotail. Recent in situ observations by the Magnetospheric Multiscale spacecraft and associated modeling have advanced our current understanding of how ionospheric ions alter the magnetic reconnection process, including its onset and efficiency. This article compiles the current understanding of the ionospheric plasma supply to the magnetosphere. It reviews both the quantification of these sources and their effects on the process of magnetic reconnection. It also provides a global description of how the ionospheric ion contribution modifies the way the solar wind couples to the Earth's magnetosphere and how these ions modify the global dynamics of the near-Earth space environment.

Plain Language Summary

Above the neutral atmosphere, space is filled with charged particles, which are tied to the Earth's magnetic field. The particles come from two sources, the solar wind and the Earth's upper atmosphere. Most of the solar wind particles are deflected by the Earth´s magnetic field, but some can penetrate into near-Earth space. The ionized layer of the upper atmosphere is continuously ejecting particles into space, which have low energies and are difficult to measure. We investigate the relative importance of the two charged particle sources for the dynamics of plasma processes in near-Earth space. In particular, we consider the effects of these sources in magnetic reconnection. Magnetic reconnection allows initially separated plasma regions to become magnetically connected and mix, and converts magnetic energy to kinetic energy of charged particles. Magnetic reconnection is the main driver of geomagnetic activity in the near-Earth space, and is responsible for the release of energy that drives a variety of space weather effects. We highlight the fact that plasma from the ionized upper atmosphere contributes a significant part of the density in the key regions where magnetic reconnection is at work, and that this contribution is larger when the geomagnetic activity is high.

Place, publisher, year, edition, pages
John Wiley & Sons, 2021
Keywords
magnetosphere, ionospheric outflow, magnetic reconnection, cold ions, heavy ions, ionosphere
National Category
Geophysics Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-457757 (URN)10.1029/2020RG000707 (DOI)000702346500002 ()
Available from: 2021-11-02 Created: 2021-11-02 Last updated: 2024-01-15Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3725-4920

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