准平行无碰撞激波的混合模拟

本文应用一维混合模拟方法数值研究了准平行无碰撞激波的结构。结果表明，激波上游的质子和准平行无碰撞激波相互作用后，有部分质子被激波反射，并向激波上游运动很长一段距离，从而激发起束流不稳定性，引起大振幅的共振右旋偏振的低频波动。这些波动在太阳风的带动下向激波下游运动，靠近激波后与激波合并，同时在激波的上游不断有新的波动产生。此过程能不断重复地进行。在平行无碰撞激波的情况下，在激波的下游还有大振幅的非共

THE HYBRID SIMULATION OF QUASI-PARALLEL COLLISIONLESS SHOCK

The structure of quasi-parallel collisionless shock is numerically studied using one dimensional hybrid simulation. The results show that after upstream protons interact with quasi-parallel collisionless shock, a part of them are reflected and travel far upstream. This leads to the generation of ion beam instabilities which in turn excite large-amplitude right-hand polarized low-frequency resonant waves. These waves are convected back downstream by solar wind and gradually merge with the shock,in the meantime new waves are generated continuously in the upstream. This process is cyclical. For parallel collisionless shock, there exist the large-amplitude right-hand polarized low-frequency non-resonant waves in the downstream. Low-frequency waves in upstream are gradually enhanced while travelling downstream, finally exceed the old shock and form a new shock.