[P-EM15] Space Plasma Physics: Theory and Simulation

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

*Yuya Fujiwara¹, Takeshi Nogi¹, Yoshiharu Omura¹ (1.Research Institute for Sustainable Humanosphere, Kyoto University)

Keywords:whistler-mode wave, triggered emission, PIC simulation

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.