Magnetic neutral point stretching and coalescence in tearing‐generated magnetohydrodynamic structures
Magnetic neutral point stretching and coalescence in tearing‐generated magnetohydrodynamic structures
复制标题
撕裂产生的磁流体动力结构中的磁中性点拉伸和合并
DOI：
10.1063/1.859648
复制
发表时间：
1991
期刊：
影响因子：
--
通讯作者：
V. Carbone
中科院分区：
文献类型：
--
作者：
F. Malara;P. Veltri;V. Carbone
使用足够高的系统长宽比对片材收缩不稳定性的时间演化进行数值研究，以允许多个不稳定波长同时增长。该数值模拟为撕裂不稳定性的非线性发展提供了新的见解。在不稳定性饱和之前，不稳定模式之间的非线性相互作用会产生局部合并现象，从而破坏较弱的电流箍缩并减少磁岛的数量。与通常的情况相反，这种合并并不是由于电流最大值之间的吸引力，而是由于与最强烈的电流收缩相关的 X 中性点的拉伸。全球扰动增长率在时间上基本保持不变，与电阻不稳定性增长率相当。
The time evolution of the instability of a sheet pinch is numerically studied using a sufficiently high ratio of system length to width in order to allow the simultaneous growth of several unstable wavelengths. This numerical simulation provides new insights into the nonlinear development of the tearing instability. Before the instability saturates, the nonlinear interactions among the unstable modes produce local coalescence phenomena that destroy the weaker current pinches and reduce the number of magnetic islands. In contrast with the usual picture, this coalescence is not due to the attraction between the current maxima, but is due to the stretching of the X‐neutral points associated with the most intense current pinches. The global perturbation growth rate remains essentially unchanged in time, being of the order of the resistive instability growth rate.