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Generation of rising‐tone chorus in a two‐dimensional mirror field by using the general curvilinear PIC code
Author(s) -
Ke Yangguang,
Gao Xinliang,
Lu Quanming,
Wang Xueyi,
Wang Shui
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2017ja024178
Subject(s) - physics , chorus , field line , magnetic field , computational physics , equator , magnetosphere particle motion , curvilinear coordinates , curvature , acoustic wave , optics , geometry , latitude , astronomy , art , literature , mathematics , quantum mechanics
Recently, the generation of rising‐tone chorus has been implemented with one‐dimensional (1‐D) particle‐in‐cell (PIC) simulations in an inhomogeneous background magnetic field, where both the propagation of waves and motion of electrons are simply forced to be parallel to the background magnetic field. In this paper, we have developed a two‐dimensional (2‐D) general curvilinear PIC simulation code and successfully reproduced rising‐tone chorus waves excited from an anisotropic electron distribution in a 2‐D mirror field. Our simulation results show that whistler waves are mainly generated around the magnetic equator and continuously gain growth during their propagation toward higher‐latitude regions. The rising‐tone chorus waves are observed off the magnetic equator, which propagate quasi‐parallel to the background magnetic field with the wave normal angle smaller than 25°. Due to the propagating effect, the wave normal angle of chorus waves is increasing during their propagation toward higher‐latitude regions along an enough curved field line. The chirping rate of chorus waves is found to be larger along a field line with a smaller curvature.