等离子体彗尾动力学的数值研究

本文基于可压缩磁流体动力学模型，数值研究了尾瓣中具有超Ａｌｆｖｅｎ速流动的等离子体彗星的动力学特征，结果表明，等离子体片和尾瓣之间的剪切等离子体流动将会激发流动撕裂模不稳定性，引起彗星等离子体片中发生磁场重联，形成磁岛和高密度的等离子体团，进而模拟了太阳风引起的局部驱动力对等离子体彗尾中磁场重联的影响，其特征时间远大于流动撕裂模，我们认为一些观测到的等离子体彗尾中的团块和彗尾截断事件可能主要与彗尾

A NUMERICAL STUDY ON DYNAMICS OF COMETARY PLASMA TAIL

In this paper,on the basis of a compressible magnetohydrodynamic model,the dynamics of the cometary plasma tail with a super-Alfvenic flow in the lobes arestudied numerically. The results show that the streaming tearing instability is excited by the sheared plasma flow which exists between the plasma sheet and the lobes.It causes magnetic reconnection and forms the magnetic islands and plasmoids with high plasma density in the plasma sheet of cometary tail.Furthermore the effect of a local driving force delivered by the solar wind on magnetic reconnection in the plasma tail of comets is also simulated.But its characteristic time is larger than that of the streaming tearing mode.It is suggested that some of knots and disconnection events observed in the plasma tail of comets may be mainly associated with the streaming tearing instability produced by the sheared plasma flow in cometary tail.