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Unraveling the Correlation Between Chorus Wave and Electron Beam‐Like Distribution in the Earth's Magnetosphere
Author(s) -
Chen Rui,
Gao Xinliang,
Lu Quanming,
Wang Shui
Publication year - 2019
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 - 10.1029/2019gl085108
Subject(s) - physics , electron , beam (structure) , magnetosphere , chorus , electric field , computational physics , wave propagation , atomic physics , cathode ray , plasma , optics , nuclear physics , art , literature , quantum mechanics
In this letter, we have investigated the correlation between lower band chorus waves and electron beam‐like distribution with long‐term THEMIS data. Cold, hot, and beam electrons are assumed in the plasma. For quasi‐parallel chorus waves, they are usually observed along with a relatively weak electron beam. Moreover, the density ratio between beam and hot electrons n b / n h is positively correlated with the wave parallel electric field and inversely correlated with the hot electron density, in agreement with a formation of the beam by Landau acceleration during wave propagation, while, along with oblique waves, there typically exists a strong electron beam. Notably, the n b / n h is found to be independent of both the parallel electric field and hot electron density, indicating that the electron beam‐like distribution should be a precondition for exciting oblique waves rather than caused by waves. Our study provides some new insights into understanding the generation and evolution of chorus waves.