Kinetic and nonlinear processes in space plasmas

摘要

Computer simulations based on full particle in cell (PIC), test particles, hybrid and Vlasov codes combined with theoretical analysis have allowed to analyze the kinetic effects of plasma which are excluded in macroscopic magnetohydynamic (MHD) approach. These effects do have important impacts via wave-particle interactions to account for plasma acceleration and heating, wave damping, particle diffusion, and wave generation. These effects lead to various types of microscopic dissipation processes (responsible for viscosity and resistivity) which can be identified and analyzed in details, in contrast with MHD approach where the corresponding source mechanisms of dissipation are ignored. In addition, kinetic effects allow the accessibility to microscales over which some processes can be initiated, in particular, for nonlinear mechanisms. This accessibility leads to some coupling of processes over micro-meso scales. A quite large variety of mechanisms is concerned by such kinetic effects. In the following sections, we will restrict our review on recent progress to three selected topics performed via theory, simulations and in strong relationship with observations. These topics are respectively (i) collisionless shocks, (ii) magnetic reconnection and (iii) nonlinear kinetic waves and structures.