报告题目：Understanding Transport Processes in the Magnetosphere Using Hybrid Simulation
报告人：林郁教授 (Physics Department, Auburn University，USA)
报告摘要：Transport processes associated with kinetic Alfven waves (KAWs) at the dayside magnetopause and in the magnetotail are investigated using three-dimensional (3-D) global and local hybrid simulations. KAWs are shown to be generated by mode conversion and magnetic reconnection. (1) KAWs are found to be a common feature of magnetic reconnection. Their generation, structures, and roles in ion heating/acceleration are illustrated for cases with various X line lengths and guide field strengths. (2) In the magnetotail, Alfven/KAWs and compressional waves are generated from the reconnection and near the global dipolarization front, with strong turbulence at the flow braking. In addition, KAWs occupy a broad region of the dipole-like field due to the mode conversion and phase mixing processes. Ion particle distributions reveal multiple populations/accelerated beams in the tail and strong perpendicular heating in the ring current region. The wave/turbulence spectrum, ion acceleration, and plasma global transport to the inner magnetosphere associated with the entropy-depleted reconnected flux tubes are presented. (3) At the magnetopause, KAWs are generated by mode conversion from fast mode compressional waves downstream of the quasi-parallel shock.The global structure and propagation of KAWs under various IMF conditions are investigated. The 3-D physics of mode conversion is crucial to plasma cross field line transport. The KAWs in the dayside and night magnetosphere carry Poynting fluxes and field-aligned currents to the ionosphere.