Electromagnetic full particle code with adaptive mesh refinement technique: Application to the current sheet evolution

We have developed a new two and a half dimensional electromagnetic particle code with adaptive mesh refinement (AMR) technique in an effort to give a self-consistent description of the dynamic change of the plasma sheet in association with magnetic reconnection, which includes multi-scale processes from the electron scale to the magnetohydrodynamic scale. The AMR technique subdivides and removes cells dynamically in accordance with a refinement criterion and it is quite effective to achieve high-resolution simulations of phenomena that locally include micro-scale processes. Since the number of particles per cell decreases in the subdivided cells and a numerical noise increases, we subdivide not only cells but also particles therein and control the number of particles per cell. Our code is checked against several well-known processes such as the Landau damping of the Langmuir waves and we show that the AMR technique and particle splitting algorithm are successfully applied to the conventional particle codes. We have also examined the nonlinear evolution of the Harris-type current sheet and realized basically the same properties as those in other full particle simulations. We show that the numbers of cells and particles are greatly reduced so that the time to complete the simulation is significantly shortened in our AMR code, which enables us to conduct large-scale simulations on the current sheet evolution.