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Effects of Nonlinear Resonance Broadening on Interactions Between Electrons and Whistler Mode Waves
Author(s) -
Cai Bin,
Wu Yifan,
Tao Xin
Publication year - 2020
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 - 10.1029/2020gl087991
Subject(s) - physics , electron , pitch angle , nonlinear system , resonance (particle physics) , test particle , computational physics , whistler , scattering , quantum electrodynamics , doppler broadening , atomic physics , classical mechanics , quantum mechanics , spectral line , geophysics
Abstract Effects of nonlinear resonance broadening on diffusion coefficients for interactions between parallel propagating whistler mode waves and relativistic electrons in a uniform magnetic field are investigated in this work using test particle simulations. In quasi‐linear theory, variations of pitch angle and energy are calculated along the unperturbed trajectory, resulting in difficulties when the pitch angle is near 90° or when wave amplitudes are large. Using a test particle simulation code, we investigate effects of nonlinear resonance broadening on scattering of electrons and compare the results with a previous nonlinear theory by Karimabadi et al. We demonstrate that Karimabadi et al.'s theory gives better agreement with test particle simulations compared with standard quasi‐linear theory, provided that the resonance broadening width is allowed to vary. Our result suggests further development of the nonlinear theory and should be useful to improve radiation belt modeling.