The Composition of Plasma inside Geostationary Orbit Based on Van Allen Probes Observations

Authors

Chao Yue, University of California, Los Angeles
Jacob Bortnik, University of California, Los Angeles
Wen Li, Boston University
Qianli Ma, University of California, Los Angeles
Matina Gkioulidou, Johns Hopkins University Applied Physics Laboratory
Geoffrey D. Reeves, Los Alamos National Laboratory
Chih Ping Wang, University of California, Los Angeles
Richard M. Thorne, University of California, Los Angeles
Anthony T.Y. Lui, Johns Hopkins University Applied Physics Laboratory
Andrew J. Gerrard, New Jersey Institute of Technology
Harlan E. Spence, University of New Hampshire Durham
Donald G. Mitchell, Johns Hopkins University Applied Physics Laboratory

Document Type

Article

Publication Date

8-1-2018

Abstract

The composition of the inner magnetosphere is of great importance for determining the plasma pressure and thus the currents and magnetic field configuration. In this study, we perform a statistical survey of equatorial plasma pressure distributions and investigate the relative contributions of ions and electron with different energies inside of geostationary orbit under two auroral electrojet levels based on over 60 months of observations from the Helium, Oxygen, Proton, and Electron and Radiation Belt Storm Probes Ion Composition Experiment mass spectrometers onboard Van Allen Probes. We find that the total and partial pressures of different species increase significantly at high auroral electrojet levels with hydrogen pressure being dominant in the plasmasphere. The pressures of the heavy ions and electrons increase outside the plasmapause and develop a strong dawn-dusk asymmetry with ion pressures peaking at dusk and electron pressure peaking at dawn. In addition, ring current hydrogen with energies ranging from 50 keV up to several hundred keV is the dominant component of plasma pressure during both quiet (>90%) and active times (>60%), while oxygen with 10 < E < 50 keV and electrons with 0.1 < E < 40 keV become important during active times contributing more than 25% and 20% on the nightside, respectively, while the helium contribution is generally small. The results presented in this study provide a global picture of the equatorial plasma pressure distributions and the associated contributions from different species with different energy ranges, which advance our knowledge of wave generation and provide models with a systematic baseline of plasma composition.

Identifier

85052501281 (Scopus)

Publication Title

Journal of Geophysical Research Space Physics

External Full Text Location

https://doi.org/10.1029/2018JA025344

e-ISSN

21699402

ISSN

21699380

First Page

6478

Last Page

6493

Issue

8

Volume

123

Grant

NNN06AA01C

Fund Ref

National Aeronautics and Space Administration

Recommended Citation

Yue, Chao; Bortnik, Jacob; Li, Wen; Ma, Qianli; Gkioulidou, Matina; Reeves, Geoffrey D.; Wang, Chih Ping; Thorne, Richard M.; Lui, Anthony T.Y.; Gerrard, Andrew J.; Spence, Harlan E.; and Mitchell, Donald G., "The Composition of Plasma inside Geostationary Orbit Based on Van Allen Probes Observations" (2018). Faculty Publications. 8476.
https://digitalcommons.njit.edu/fac_pubs/8476