Theoretical Computation of Anomalous Resistivity for Substorm and Reconnection Onset

提出的研究项目包括对薄电流片中异常电阻率的非线性理论的理论研究。异常的电阻率被认为在地球磁层亚暴的触发中起着重要作用。反常电阻率的概念在文献中被广泛引用，但还没有系统的理论讨论可以很容易地应用于磁重联问题。这个项目将发展一个自洽的反常耗散理论，它是由高频电磁不稳定引起的，称为修正的双流不稳定性和低混合漂移不稳定性。就在重新连接开始之前，这些不稳定性很可能在薄电流片中活跃。在当代关于重联的研究中(无论是理论还是仿真)，通常都是以简单的Harris模型作为起点。然而，哈里斯模型不能很好地描述亚暴爆发前的当前冰盖结构。因此，拟议的研究将通过推广惯用的哈里斯模型来模拟当前的纸张结构。该方法将是一个非局域的、动力学的、线性的弗拉索夫理论，加上对异常传输系数的准线性处理。然后用数值方法求解理论方程。电磁波动的激发与亚暴或重新连接的开始相关的概念源于公认的(但了解不多的)实验证据，例如MRX实验室实验和AMPTE航天器测量。

The proposed research project comprises a theoretical study of the non-linear theory of anomalous resistivity in thin current sheets. Anomalous resistivity is thought to play an important role in the triggering of magnetic substorms in Earth's magnetosphere. The concept of anomalous resistivity is widely invoked in the literature, but no systematic theoretical discussion has been carried out which can be readily applied to the problem of magnetic reconnection. This project will develop a self-consistent theory of anomalous dissipation which arises from the excitation of a high-frequency electromagnetic instability called the modified-two-stream instability and the lower-hybrid drift instability. These instabilities are likely to be active in thin current sheets just prior to the onset of reconnection. In contemporary research on reconnection (both theory and simulation), the simple Harris model is usually used as the starting point. However, the current sheet structure just prior to the substorm onset cannot be described adequately by the Harris model. The proposed research will therefore model the current sheet structure by generalizing the customary Harris model. The methodology will be a non-local, kinetic, linear Vlasov theory coupled with quasilinear treatment of the anomalous transport coefficient. The theoretical equations will then be solved by numerical means. The notion of excitation of electromagnetic fluctuations being correlated with the onset of substorm or reconnection derives from well-established (but poorly understood) experimental evidence such as the MRX laboratory experiment and AMPTE spacecraft measurements.