空间等离子体与垂直无碰撞激波相互作用的数值实验

A NUMERICAL EXPERIMENT OF INTERACTION BETWEEN SPACE PLASMA AND PERPENDICULAR COLLISIONLESS SHOCK

应用混合模拟方法数值研究了高Ａｌｆｖｅｎ—Ｍａｃｈ数垂直无碰撞激波与等离子体间的相互作用。结果表明，激波上游的磁场非常稳定，粒子分布近似为Ｍａｘｗｅｌｌ分布。激波下游磁场存在不规则的湍动，质子分布有一个高能尾，且有些质子被激波反射。跟踪少量高速质子的计算结果表明，在ｔ＝４０Ω时约有４０％的质于被激波反射，而７％质子可被加速，最大速度值可达到２０ＶＡ激波区的电场分布对质子的减速或加速起了主要的作用。

The interaction between space plasma and a high Alfven-Mach number perpendicular collisionless shock using a hybird simulation is numerically studied. The results show that in the upstream the magnetic field is very stable, and the distribution of the proton is nearly a Maxwell distribution. In the downstream the magnetic field eaists the irregular turbulence. The distribution of protons has a high energy tail and few protons 4ie reflected. Following some protons with high velocity, it is found that at t=40Ω about 40% of protons are reflectal by shock, and 7% of protons are accekerated(maximum velvcity up to 20VA). The electric field in shock region has gureat influence on the deceleration and acceleration of protons.