Open AccessVelocity distributions of superthermal electrons fitted with a power law function in the magnetosheath: Cluster observations
Author(s) -
Lu Quanming,
Shan Lican,
Shen Chenlong,
Zhang Tielong,
Li Yiren,
Wang Shui
Publication year - 2011
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja016118
Subject(s) - magnetosheath , physics , electron , power law , computational physics , distribution function , pitch angle , whistler , atomic physics , plasma , magnetosphere , geophysics , quantum mechanics , magnetopause , mathematics , statistics
Satellite observations have revealed that superthermal electrons in space plasma generally possess a power law distribution. In this paper, we utilize a power law function to model the omnidirectional differential fluxes of superthermal electrons observed by Cluster in the magnetosheath. By assuming an isotropic pitch angle distribution and performing a nonlinear least squares fitting, we can calculate the index α of the power law distribution of the superthermal electrons. We found that in the magnetosheath the indices α of the power law distributions decrease with the increase of ω pe /Ω e . It is consistent with the results of the recent particle‐in‐cell simulations, which described the electron distributions scattered by enhanced whistler waves. This is the first reported observation of this relation in space plasma.