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Nonlinear Landau resonant scattering of near equatorially mirroring radiation belt electrons by oblique EMIC waves
Author(s) -
Wang Bin,
Su Zhenpeng,
Zhang Yan,
Shi Shengwei,
Wang Geng
Publication year - 2016
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 - 10.1002/2016gl068467
Subject(s) - physics , electron , landau damping , pitch angle , van allen radiation belt , plasmoid , scattering , computational physics , electromagnetic radiation , atomic physics , plasma , geophysics , optics , magnetosphere , magnetic reconnection , nuclear physics
In response to solar wind disturbances, radiation belt (a few hundreds of keV to several MeV) electron fluxes can be depleted significantly over the entire equatorial pitch angle range. The frequently mentioned cyclotron resonant scattering is applicable only for electrons mirroring off the equator. Here we propose a new physical mechanism, nonlinear Landau resonance with oblique electromagnetic ion cyclotron (EMIC) waves, to effectively scatter the near equatorially mirroring electrons. Our test particle simulations show that the nonlinear Landau trapping can occur over a wide energy range and yield the net decrease in equatorial pitch angle Δ α eq ≈10° within several seconds. Our parametric studies further reveal that this nonlinear Landau‐trapping process is favored by a low plasma density, an intense wave field, a high wave frequency close to ion gyrofrequencies, and a large wave normal angle.