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Nonlinear Coupling Between Whistler‐Mode Chorus and Electron Cyclotron Harmonic Waves in the Magnetosphere
Author(s) -
Gao Zhonglei,
Su Zhenpeng,
Xiao Fuliang,
Summers Danny,
Liu Nigang,
Zheng Huinan,
Wang Yuming,
Wei Fengsi,
Wang Shui
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 - 10.1029/2018gl080635
Subject(s) - physics , magnetosphere , chorus , electron , whistler , computational physics , dispersion relation , harmonic , van allen radiation belt , electron precipitation , particle acceleration , electromagnetic radiation , cyclotron , quantum electrodynamics , atomic physics , plasma , optics , acoustics , quantum mechanics , art , literature
Electromagnetic whistler‐mode chorus and electrostatic electron cyclotron harmonic (ECH) waves can contribute significantly to auroral electron precipitation and radiation belt electron acceleration. In the past, linear and nonlinear wave‐particle interactions have been proposed to explain the occurrences of these magnetospheric waves. By analyzing Van Allen Probes data, we present here the first evidence for nonlinear coupling between chorus and ECH waves. The sum‐frequency and difference‐frequency interactions produced the ECH sidebands with discrete frequency sweeping structures exactly corresponding to the chorus rising tones. The newly generated weak sidebands did not satisfy the original electrostatic wave dispersion relation. After the generation of chorus and normal ECH waves by hot electron instabilities, the nonlinear wave‐wave interactions could additionally redistribute energy among the resonant waves, potentially affecting to some extent the magnetospheric electron dynamics.