GEM: On the Quiet-Time Flow Variability in the Earth's Plasma Sheet

对地球等离子体片低速流动状态的特性进行了统计分析。低流态等离子体片(即静止期等离子体片)被定义为PI以前研究的突发性整体流动事件(BBF事件)状态的补充。低流动状态是等离子体片中流动的最可能状态，因为它包括可用等离子体片数据集的92-95%。这种流动状态具有平均流动模式，该平均流动模式可以根据等离子体片的2-流体图像来解释。这一流动模式将利用目前的磁场模型绘制在电离层上，并将审查这一模式对货币基金组织部门的依赖性。非BBF流动的变化比等离子体层中的平均流动速度大许多倍，即使在低声发射条件下也会持续存在。流动的不稳定可能会使等离子体片中的对流继续进行，这与压力平衡不一致的论点相反。因此，将研究不同地磁条件下、X-Y平面上不同位置的流量变率，以及地球对流与流量变率之间的关系。流动的可变性将包含在等离子体片平衡的定性模型中。对静止等离子体片流场的理论指导的统计分析渴望表征等离子体片基态的基本性质及其与全球磁层环流的关系。

A statistical analysis of the properties of the low-speed flow state of the earth's plasma sheet is approved. The low flow state plasma sheet (i.e., the quiet-time plasma sheet), is defined as the complementary of the bursty bulk flow event (BBF event) state, previously studied by the PI. The low flow state is the most probable state of the flow in the plasma sheet as it comprises 92- 95% of the available plasma sheet datasets. This flow state possesses an average flow pattern that can be explained in terms of a 2-fluid picture of the plasma sheet. That flow pattern will be mapped on the ionosphere by use of current magnetic field models, and the dependence of that pattern on the IMF sector will be examined. The non-BBF flows have a variance that is many times larger than the average flow speed in the plasma sheet and persist even during low AE conditions. The unsteadiness of the flow may allow convection in the plasma sheet to proceed, contrary to the pressure balance inconsistency argument. Thus the flow variability under different geomagnetic conditions, and in different locations on the X-Y plane will be studied as well as the correlation between earthward convection and flow variability. The flow variability will be incorporated in a qualitative model of the plasma sheet equilibrium. The theory-guided statistical analysis of the quiet plasma sheet flow field aspires to characterize the basic properties of the ground state of the plasma sheet and its relevance to global magnetospheric circulation.