Dynamics of structure formation and self-organization in open systems

答：在无碰撞重新连接的时间行为中，有稳定的区域和间歇的区域，这取决于外部驱动流的空间分布。在小输入窗口的情况下，实现了稳定的无碰撞重联，其中重联速率与上游边界的磁通输入速率是平衡的，整个磁重联的动态过程主要由离子动力学控制：随着窗口尺寸的增大，电流片变长，这有利于激发电子撕裂不稳定性。该系统演变成间歇状态，其中在电流片中频繁地产生磁岛。在离子和电子动力学的共同作用下，在电流密度分布中形成了双尺度结构。与中心电子电流片中的电子弯曲运动有关的电子压张量是产生重联电磁场…的主要原因在二维稳态重联中，虽然整个重联系统的演化主要受外部条件的控制，但中性片上的ELD更大。B.在三维情况下，等离子体不稳定性被激发，并影响无碰撞重联的动力学行为。在外部驱动源存在的情况下，外围激发的低杂波漂移波向中性片传播，从而在电流片中产生反常的电阻率。因此，外部驱动电场穿透到电流片中，并在中性片处触发磁重联。由于磁场重联，在下游产生了磁岛，但它们变得不稳定，不受扭结不稳定性的影响。当磁岛通过下游边界消失后，系统暂时松弛到准稳态。电流片中与离子旋转频率相当的低频电磁模式(漂移-扭结不稳定性)在电流片中缓慢增长，改变了电流片的空间结构。c.通过二维和三维电磁粒子模拟，研究了空心电流剖面的自生过程及其对倾斜不稳定性的影响。该系统自发地从磁流体动平衡状态松弛到动态流平衡状态，此时电子电流分布变为空洞。在中空电流剖面和高分离线β值的情况下，倾斜不稳定性的增长率小于在峰值电流剖面情况下的增长率。当磁分离线形状较长时，不稳定区域位于边缘附近，对倾斜不稳定起到有效的稳定作用。较少

A. There are a steady regime and an intermittent regime in the temporal behavior of collisionless reconnection, dependently on the spatial profile of an external driving flow. The steady collisionless reconnection is realized in the case of small input window size, in which the reconnection rate is balanced with the flux input rate at the upstream boundary and the global dynamic process of magnetic reconnection is dominantly controlled by ion dynamics : As the window size increases, the current sheet becomes longer, which is favorable to the excitation of an electron tearing instability. The system evolves into an intermittent regime, in which magnetic islands are frequently generated in the current sheet. Two-scale structure is formed in the current density profile through combined actions of both ion and electron dynamics. Electron pressure tensor associated with electron meandering motion in the central electron current sheet is a main cause of generation of reconnection electric fi … More eld at neutral sheet in two-dimensional steady reconnection, although the evolution of the whole reconnection system is controlled mainly by an external condition.B. In three-dimensional case plasma instabilities are excited and affect the dynamical behavior of collisionless reconnection. In the presence of an external driving source the lower hybrid drift waves excited in the periphery propagate toward the neutral sheet and thus generate anomalous resistivity in the current sheet. Consequently, the external driving electric field penetrates into the current sheet and triggers magnetic reconnection at the neutral sheet. Magnetic islands are created in the downstream as a result of magnetic reconnection, but they become unstable against the kink instability. After magnetic islands disappear through the downstream boundary, the system relaxes into a quasi-steady state temporarily. An electromagnetic (EM) mode with a low-frequency comparable to ion gyration frequency (drift-kink instability) grows slowly in the current sheet and modifies the spatial structure.C. Self-generation process of hollow current profile and its influence on tilting instability in field-reversed configurations are investigated by means of two-dimensional and three-dimensional EM particle simulations. The system spontaneously relaxes from a magnetohydrodynamic equilibrium toward a kinetic one, in which the electron current profile becomes hollow. Growth rate of the tilting instability in the case of the hollow current profile and high separatrix beta value is smaller than that in the case of the peaked current profile. When magnetic separatrix shape is much prolate, the unstable region is localized near the edges, and stabilization of the tilt instability becomes effective. Less