[P-EM12] Dynamics of the Inner Magnetospheric System

[PEM12-10] Modeling of outer radiation belt electron dynamics associated with whistler mode chorus emissions via Green’s function method

*Yikai Hsieh¹, Yoshiharu Omura¹ (1.Reserach Institute for Sustainable Humanosphere, Kyoto University)

Keywords:outer radiation belt, whistler mode chorus emissions, Green's function, energetic electron precipitation, Landau resonance, cyclotron resonance

Energetic electron accelerations and precipitations in the Earth’s outer radiation belt are highly associated with wave-particle interactions between whistler mode chorus waves and electrons. Two main processes take place in the whistler mode wave-particle interactions. One is the untrapped resonance process, which makes electron energy slightly smaller and lowers the equatorial pitch angle of the electron. The other is the nonlinear trapping process, which makes effective energy gain of the resonant electrons. We perform test particle simulation in a 3D dipole field to reproduce the interactions in the radiation belt and investigate the electron acceleration and precipitation interacting with both parallel and obliquely propagating chorus emissions. We build up a database of Green’s functions, which are treated as results of the input electrons interacting with one emission, for a large number of electrons interacting with whistler mode chorus emissions. The formation processes and the loss processes of the outer radiation belt electron fluxes interacting with consecutive chorus emissions are traced by applying the convolution integrals for the Green’s functions. In the acceleration parts, MeV electrons are generated promptly due to the combination of cyclotron resonance and Landau resonance of oblique chorus waves. We compare the precipitation phenomena between parallel waves and oblique waves, and the results show that oblique chorus emissions lead to more electron precipitation than that led by parallel chorus emissions. Since the precipitations by chorus emissions are much less than the accelerations, in this study we further take energetic electron precipitations by EMIC waves into account to simulate the overall acceleration and loss processes in the outer radiation belt.