Three-Dimensional Dynamics of Thin Current Sheets and Their Role in the Triggering and Spatio-Temporal Evolution of Magnetotail Substorms

调查人员将对磁层亚暴增长阶段形成的薄电流片进行分析和高分辨率计算研究。 这些电流片在磁尾中被观测到，并可能在亚暴发生中起重要作用。 以前的计算是在良好的定量雅阁与多卫星观测的空间和时间特性的薄电流片在缓慢增长和冲动的预发作阶段的亚暴，并导致识别的压力驱动的气球不稳定性作为一个潜在的机制亚暴触发。 这项调查将使用霍尔磁流体力学的理论框架，包括一个广义欧姆定律与霍尔电流和电子压力梯度条款。 任务包括发展更完整的重联理论、薄电流片和磁尾亚暴动力学，以及有和无速度剪切的压力驱动气球不稳定性之间的动力学耦合。

The investigators will conduct analytical and high-resolution computational studies of thin current sheets which are formed during the growth phase of magnetospheric substorms. These current sheets are observed in the magnetotail and may play an important role in substorm onset. Previous calculations are in good quantitative accord with multi-satellite observations of the spatial and temporal characteristics of thin current sheets in the slow growth and impulsive pre-onset phases of substorms, and have led to the identification of the pressure-driven ballooning instability as a potential mechanism for substorm trigger. This investigation will use the theoretical framework of Hall magnetohydrodynamics, including a generalized Ohm's law with Hall current and electron pressure gradient terms. Tasks include the development of a more complete theory of reconnection, thin current sheet and magnetotail substorm dynamics, and dynamical coupling between pressure-driven ballooning instabilities with and without velocity shears.