Counter-Streaming Interaction between Fast Magnetosonic Wave and Radiation Belt Electrons
ZHU Hui, SU Zhen-Peng, ZHENG Hui-Nan**
CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026
Abstract：Fast magnetosonic (MS) waves have been suggested to be able to effectively accelerate radiation belt electrons. We present gyro-averaged test-particle simulations to investigate counter-streaming interaction between MS wave and radiation belt electrons. It is found that an MS wave can significantly scatter counter-streaming electrons through a non-resonant process. The corresponding energy diffusion coefficients for counter-streaming interaction are always comparable to those for co-streaming interaction, independent of wave normal angle. The pitch-angle and cross diffusion coefficients of counter-streaming interaction are much smaller than those of co-streaming interaction for small normal angles, while they become comparable for large normal angles. Moreover, the bounce-averaged diffusion coefficients exhibit quite different distribution from those for co-streaming or counter-streaming alone in the pitch-angle-energy space. These results suggest that the non-resonant effect associated with counter-streaming interaction is indispensable for the acceleration processes driven by an MS wave.
2013, Vol. 30 
