We carried out numerical simulations to investigate electron dynamics at the collisionless shock transition region where most of bulk flow energy is released rapidly. Our particle-in-cell simulation resolves the electron plasma oscillation in time and the electron inertia length in space. We have shown that plasma instability between inflow electron and reflected ions (Buneman instability) grows into a strong nonlinear phase where a large-amplitude coherent wave structure (electron hole) plays an important role to generate energetic and hot electrons. The plasma instability occurs at the shock transition region and is sensitive to the plasma physical conditions, such as magnetic field strength and initial flow speed and its dispersion (effective temperature). Besides well known parameters such as Mach number and plasma β (the ratio of thermal energy to magnetic energy), the ratio of electron plasma oscillation frequency to electron gyration frequency is another important parameter for electron dynamics.
8th Asian-Pacific Regional Meeting, Volume II
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