日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM13] 内部磁気圏

2019年5月29日(水) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:海老原 祐輔(京都大学生存圏研究所)、Danny Summers(Memorial University of Newfoundland)、三好 由純(名古屋大学宇宙地球環境研究所)、齊藤 慎司(名古屋大学 大学院理学研究科)

[PEM13-P07] Amplitude dependence of whistler wave motion on electron scattering process

*伊藤 義起1三好 由純1齊藤 慎司1 (1.名古屋大学宇宙地球環境研究所)

Whistler mode chorus waves cause scattering and acceleration of energetic electrons in the inner magnetosphere. The interaction processes have been modeled as diffusive process. The pitch angle diffusion coefficients of the pitch angle scattering depend on the power of chorus waves, so that it is expected that the scattering rate also depends on the wave amplitude. On the other hand, several previous studies indicated that the Lorentz force by the wave magnetic field is larger than the mirror force if the wave amplitudes increase and the electron trajectories in the velocity space are different from the diffusive distributions. In this study, we investigate chorus wave amplitude dependence of electron scattering using the GEMSIS-RBW simulation code. The RBW simulation demonstrates generation of periodical rising-tone chorus waves propagating along a magnetic field line to higher latitudes, and calculates local pitch angle and energy change by the imposed waves on the field line. At small wave amplitudes, time variations of pitch angle and energy of electrons are similar to diffusive process. At large wave amplitudes, some electrons increase both pitch angle and energy at interaction with the first rising tone, and then they decrease these parameters at interaction with the second rising tone. The process in the first rising tone seems to be the phase trapping, while the process in the second rising tone seems to be dislocation. Therefore, nonlinear scattering processes, which are phase trapping and dislocations, occur during the interactions with periodical rising-tone chorus waves with large amplitudes, which are quite different from quasi-linear scattering process.