【摘要】 在粒子模拟的PIC(particle in cell)模式中,与场有关的物理量如电磁场等分配在固定的网格点上,而粒子则可在计算区域的任意位置上.设计了一个二维三分量的粒子模拟程序,并用它计算了空间物理中两种常见的物理现象:束流不稳定性和磁场重联.在束流不稳定性问题中,一束速度为Vb=10VA(VA为Alfv啨n速度)的等离子体在背景等离子中运动,通过波粒相互作用可激发沿磁场方向传播的Alfv啨n波.在磁场重联问题中,具有Harris形态的电流片可自发地引起磁场重联,并且By分量的磁场具有四极形分布.更多还原

【Abstract】 In the PIC method of particle simulations,the physical variables related to the fields are assigned to the grids,while the particles can be anywhere in the simulation domain.Using this method,we design a 2D particle simulation code,and numerically study two common physical phenomena in space physics:beam instability and magnetic reconnection.In the beam instability,the beam plasma streams in the background plasma with the velocity V \-b=10 V \-A( V \-A is Alfvén speed),and the Alfvén waves are excited through wave-particle interactions.In the magnetic reconnection,the Harris current sheet can induce the magnetic reconnection,and the B\-y shows quadrupolar structure.更多还原