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Ion and Electron κ Distribution Functions Along the Plasma Sheet
Author(s) -
Espinoza C. M.,
Stepanova M.,
Moya P. S.,
Antonova E. E.,
Valdivia J. A.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl078631
Subject(s) - plasma sheet , ion , physics , electron , asymmetry , plasma , spectral line , flux (metallurgy) , atomic physics , electron temperature , magnetosphere , geophysics , computational physics , materials science , astronomy , quantum mechanics , metallurgy
We use kappa distributions to model thousands of ion and electron flux spectra along the plasma sheet and analyze the variation of the spectral index κ and the temperature T in this region. We find that κ distributions are ubiquitous and fit well ion and electron flux spectra during quiet times, and during the expansion and recovery phases of substorms. Near Earth, and up to ∼12 R E , the κ indices are different than the rest of the plasma sheet, both for ions ( κ i ) and electrons ( κ e ). There is a significant dawn‐dusk asymmetry in κ i toward the tail, which is enhanced during substorms. The ions also exhibit a permanent temperature asymmetry, determined by a colder dawnside. The whole tail becomes hotter during substorms, but it appears that most of the energy is deposited near Earth.