准平行无碰撞激波上游能量粒子的观测研究

通过Cluster卫星在2005年3月16日观测到的一个准平行激波观测事例，研究了准平行激波上游低频等离子体波动与能量离子之间的关系.卫星观测结果表明，在准平行激波上游，离子微分能通量受到了非线性波动的调制.在磁场强度较小区域，离子微分能通量较高.产生这种现象的可能原因是准平行激波上游的非线性波动可以捕获离子，被捕获的离子在波动中来回弹跳并被电场加速，从而导致磁场强度较小区域离子微分能通量较高.这一观测结果与已有的混合模拟结果相吻合.

Observations of energetic particles in the upstream of a quasi-parallel collisionless shock

With the Cluster observations of a quasi-parallel shock on 16 March 2005, relationship between the upstream low-frequency waves and the energetic ions (about several keV) has been studied. The observation results show that there are full of waves in the upstream of the shock which can interact with the upstream plasma. The differential energy flux of energetic ions in the upstream is dependent on the magnetic field strength of these waves. The energetic ion energy flux is higher in the regions with a weaker magnetic field. The possible explanation is that the ions can be trapped by the nonlinear upstream waves. Then the energetic ions were accelerated by the electric field every time when they bounced in these nonlinear waves. Our observation results are consistent with the recent hybrid simulation results.