亚暴膨胀相近磁尾位形不稳定性模型Ⅱ.中磁尾等离子体流与近磁尾亚暴活动的关系

在单流体MHD近似下，研究了有背景等离子体流存在时的近磁尾位形不稳定性．分析表明，等离子体地向流使两支漂移气球模DBM1和DBM2的不稳定增长更快．与卫星观测资料对比显示，诸多的观测观象与本模型的预言一致．这个结果对中磁尾磁场重联及高速等离子体流与亚暴膨胀相在近地触发之间的关系给出了新的解释．

A SUBSTORM EXPANSION MODEL BASED ON CONFIGURATION INSTABILITY OF THE NEAR-EARTH MAGNETOTAIL： THE RELATION BETWEEN PLASMA FLOW IN THE MIDTAIL AND SUBSTORM ACTIVITY IN THE NEAR-EARTH MAGNETOTAIL

One-fluid MHD approao is used to investigate configuration instability in me presence of plasma flow prior to onset of the substorm expansion phase in the near-Earth magnetotail． The results show that two drift ballooning modes DBMI and DBM2 become more unstable and grow more rapidly in presence of an earthward plasma flow Comparison of the theory presented here with GEOS2observations indicate that a number of observations are consistent with the model discussed in this paper This may give a new explanation to the Mation between the magnetic rerennection and resulting plasma flow in the midtail and the onset of the substorm expansion phase in the near-Earth magnetotail