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Title: Plasma Anisotropies and Currents in the Near-Earth Plasma Sheet and Inner Magnetosphere

Abstract

The region occupying radial distances of ~3–9 Earth radii (R E) in the nightside includes the near-Earth plasma sheet with stretched magnetic field lines and the inner magnetosphere with strong dipolar magnetic field. In this region, the plasma flow energy, which was injected into the inner magnetosphere from the magnetotail, is converted to particle heating and electromagnetic wave generation. These important processes are controlled by plasma anisotropies, which are the focus here. Using measurements of Time History of Events and Macroscale Interactions during Substorms and Van Allen Probes in this transition region we obtain radial profiles of ion and electron temperatures and anisotropies for various geomagnetic activity levels. Ion and electron anisotropies vary with the geomagnetic activity in opposite directions. Parallel anisotropic ions are observed together with transversely anisotropic electrons, whereas the change of ion anisotropy from parallel to transverse (with increasing K p) is accompanied by the electron anisotropy changing from transverse to parallel. Finally, based on plasma anisotropy observations, we estimate that the anisotropy-related currents (curvature currents) are about 10–20% of the diamagnetic currents.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [2]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]
  1. Univ. of California, Los Angeles, CA (United States). Inst. of Geophysics and Planetary Physics; Russian Academy of Sciences (RAS), Moscow (Russian Federation). Space Research Inst.
  2. Univ. of California, Los Angeles, CA (United States). Inst. of Geophysics and Planetary Physics
  3. Univ. of New Hampshire, Durham, NH (United States). Inst. for the Study of Earth, Oceans, and Space
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); New Mexico Consortium, Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Los Angeles, CA (United States)
Sponsoring Org.:
USDOE; National Aeronautic and Space Administration (NASA)
OSTI Identifier:
1482009
Report Number(s):
LA-UR-18-27263
Journal ID: ISSN 2169-9380
Grant/Contract Number:  
AC52-06NA25396; NNX16AF84G; NAS5-02099; NAS5-01072; NNN06AA01C
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 7; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 79 ASTRONOMY AND ASTROPHYSICS; plasma sheet; injections; inner magnetosphere; plasma currents

Citation Formats

Artemyev, A. V., Zhang, X. -J., Angelopoulos, V., Runov, A., Spence, H. E., and Larsen, B. A. Plasma Anisotropies and Currents in the Near-Earth Plasma Sheet and Inner Magnetosphere. United States: N. p., 2018. Web. doi:10.1029/2018JA025232.
Artemyev, A. V., Zhang, X. -J., Angelopoulos, V., Runov, A., Spence, H. E., & Larsen, B. A. Plasma Anisotropies and Currents in the Near-Earth Plasma Sheet and Inner Magnetosphere. United States. doi:10.1029/2018JA025232.
Artemyev, A. V., Zhang, X. -J., Angelopoulos, V., Runov, A., Spence, H. E., and Larsen, B. A. Sat . "Plasma Anisotropies and Currents in the Near-Earth Plasma Sheet and Inner Magnetosphere". United States. doi:10.1029/2018JA025232. https://www.osti.gov/servlets/purl/1482009.
@article{osti_1482009,
title = {Plasma Anisotropies and Currents in the Near-Earth Plasma Sheet and Inner Magnetosphere},
author = {Artemyev, A. V. and Zhang, X. -J. and Angelopoulos, V. and Runov, A. and Spence, H. E. and Larsen, B. A.},
abstractNote = {The region occupying radial distances of ~3–9 Earth radii (RE) in the nightside includes the near-Earth plasma sheet with stretched magnetic field lines and the inner magnetosphere with strong dipolar magnetic field. In this region, the plasma flow energy, which was injected into the inner magnetosphere from the magnetotail, is converted to particle heating and electromagnetic wave generation. These important processes are controlled by plasma anisotropies, which are the focus here. Using measurements of Time History of Events and Macroscale Interactions during Substorms and Van Allen Probes in this transition region we obtain radial profiles of ion and electron temperatures and anisotropies for various geomagnetic activity levels. Ion and electron anisotropies vary with the geomagnetic activity in opposite directions. Parallel anisotropic ions are observed together with transversely anisotropic electrons, whereas the change of ion anisotropy from parallel to transverse (with increasing Kp) is accompanied by the electron anisotropy changing from transverse to parallel. Finally, based on plasma anisotropy observations, we estimate that the anisotropy-related currents (curvature currents) are about 10–20% of the diamagnetic currents.},
doi = {10.1029/2018JA025232},
journal = {Journal of Geophysical Research. Space Physics},
issn = {2169-9380},
number = 7,
volume = 123,
place = {United States},
year = {2018},
month = {6}
}

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