[P-EM15] 宇宙プラズマ理論・シミュレーション

[PEM15-02] Simulation for wave-particle interactions of triggered emissions in a uniform magnetic field

*藤原 悠也¹、野儀 武志¹、大村 善治¹ (1.京都大学生存圏研究所)

キーワード：ホイッスラーモード波動、トリガード放射、PICシミュレーション

One-dimensional electromagnetic particle simulations were performed for the study of nonlinear process of the whistler-mode triggered emissions in a uniform magnetic field. We put cold and hot electrons initialized by bi-Maxwellian and subtracted bi-Maxwellian distributions, respectively. Driving two orthogonally aligned antennas by right-handed polarized external currents oscillating with frequencies below the electron cyclotron frequency, we generate whistler-mode triggering waves in the simulation system. We report the characteristics of the triggered emissions in terms of the duration and frequency of the triggering wave. In the cases with rising-tone emissions, we analyze dynamics of resonant electrons in the velocity phase space based on the nonlinear wave growth theory. We find that the formation of an electron hole generates rising-tone emissions after the termination of the triggering waves. In the present study, we discuss the initial process of the formation of an electron hole and hill during triggering waves, which causes frequency variations from the constant triggering frequency.