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Farrugia, C. J., Cohen, I. J., Vasquez, B. J., Lugaz, N., Alm, L., Torbert, R. B., . . . Pollock, C. J. (2018). Effects in the Near-Magnetopause Magnetosheath Elicited by Large-Amplitube Alfvenic Fluctuations Terminating in a Field and Flow Discontinuity. Journal of Geophysical Research - Space Physics, 123(11), 8983-9004
Open this publication in new window or tab >>Effects in the Near-Magnetopause Magnetosheath Elicited by Large-Amplitube Alfvenic Fluctuations Terminating in a Field and Flow Discontinuity
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2018 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 11, p. 8983-9004Article in journal (Refereed) Published
Abstract [en]

In this paper we report on a sequence of large-amplitude Alfvenic fluctuations terminating in a field and flow discontinuity and their effects on electromagnetic fields and plasmas in the near-magnetopause magnetosheath. An arc-polarized structure in the magnetic field was observed by the Time History of Events and Macroscale Interactions during Substorms-C in the solar wind, indicative of nonlinear Alfven waves. It ends with a combined tangential discontinuity/vortex sheet, which is strongly inclined to the ecliptic plane and at which there is a sharp rise in the density and a drop in temperature. Several effects resulting from this structure were observed by the Magnetospheric Multiscale spacecraft in the magnetosheath close to the subsolar point (11:30 magnetic local time) and somewhat south of the geomagnetic equator (-33 degrees magnetic latitude): (i) kinetic Alfven waves; (ii) a peaking of the electric and magnetic field strengths where E . J becomes strong and negative (-1 nW/m(3)) just prior to an abrupt dropout of the fields; (iii) evolution in the pitch angle distribution of energetic (a few tens of kilo-electron-volts) ions (H+, Hen+, and On+) and electrons inside a high-density region, which we attribute to gyrosounding of the tangential discontinuity/vortex sheet structure passing by the spacecraft; (iv) field-aligned acceleration of ions and electrons that could be associated with localized magnetosheath reconnection inside the high-density region; and (v) variable and strong flow changes, which we argue to be unrelated to reconnection at partial magnetopause crossings and likely result from deflections of magnetosheath flow by a locally deformed, oscillating magnetopause.

Place, publisher, year, edition, pages
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Fusion, Plasma and Space Physics Geophysics Astronomy, Astrophysics and Cosmology
urn:nbn:se:uu:diva-372831 (URN)10.1029/2018JA025724 (DOI)000453227400007 ()
Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-12-12Bibliographically approved
ORCID iD: ORCID iD iconorcid.org/0000-0002-6004-8861

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