HR: 0800h
AN: SM51A-1268    [Abstracts]
TI: Generation Mechanism of VLF Triggered Emission : A Simulation Study by Self-Consistent Particle Code
AU: * Katoh, Y
EM: yuto@rish.kyoto-u.ac.jp
AF: Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AU: Omura, Y
EM: omura@rish.kyoto-u.ac.jp
AF: Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AB: In this paper we challenge to clarify the role of nonlinear trapping on frequency variation of whistler mode waves including the effect of magnetic field inhomogeneity by using one dimensional, self-consistent simulation model. For several decades, generation mechanism of VLF triggered emission has been a mystery in the field of nonlinear wave particle interactions. The effect of magnetic field inhomogeneity on the modulation of whistler mode waves has been studied by previous theories and simulations. However, because of its complexity of the wave particle interaction, detailed physical processes has not been clarified yet. Previous studies revealed that both wave amplitude and wave frequency of coherent whistler mode waves are strongly affected by nonlinear resonant currents formed by trapped electrons in an inhomogeneous magnetic field. It is widely recognized that such nonlinear effect plays an important role in the excitation mechanism of VLF triggered emissions in the inner magnetosphere. In this current of study, we developed a self-consistent particle simulation code with non-uniform geomagnetic field by using electron hybrid model. Our simulation model successfully reproduce the frequency variation of triggered emission and enables us to study detailed physics of triggering mechanism. Based on the simulation results, we discuss the relation between variation of whistler mode waves and nonlinearly trapped/untrapped electrons in the non-uniform geomagnetic field.
DE: 2720 Energetic particles: trapped
DE: 2753 Numerical modeling
DE: 7829 Kinetic waves and instabilities
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005