Magnetic field-line reconnexion by localized enhancement of resistivity. Part 4. Dependence on the magnitude of resistivity
Magnetic field-line reconnexion by localized enhancement of resistivity. Part 4. Dependence on the magnitude of resistivity
复制标题
通过局部增强电阻率来重新连接磁场线。
DOI：
10.1017/s0022377800009880
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发表时间：
1979
影响因子：
2.5
通讯作者：
T. Tsuda
中科院分区：
文献类型：
--
作者：
M. Ugai;T. Tsuda
本文定量地研究了磁中性点附近局部电阻率增强的大小对快速勘探过程的影响。结果表明，准稳态Petschek型配置成立，一个为每个不同的施加局部电阻率增强。准稳态结构的基本结构在很大程度上由局部增强电阻率的初始缩进值控制。特别值得注意的是，随着局部增强电阻率变小，扩散区的宽度变小。我们发现，每一个准定常的配置提出了没有比Petschek型配置，对应于相关的磁雷诺数的允许的最大reconnancial率。我们还看到，快速再探测率的大小与扩散区的局部电阻率有很弱的依赖关系。当从另一个角度重新考虑这个问题时，我们的数值结果与以前关于快速侦察问题的理论工作是非常一致的。因此，我们建议，快速reconnancies的过程应被视为一个总的不稳定性，固有的电流片系统本身，可以触发一些局部发病的异常电阻率。
The present paper quantitatively examines how the process of fast reconnexion depends on the magnitude of the local resistivity enhanced in the vicinity of the magnetic neutral point. It is shown that quasi-steady Petschek-type configurations are set up, one for each of the variously imposed local resistivity enhancements. The fundamental structure of the quasi-steady configuration is largely controlled by the initially indented value of locally enhanced resistivity. It is especially remarked that the width of the diffusion region becomes smaller as the locally enhanced resistivity becomes smaller. We find that each of the quasi-steady configurations presents nothing other than the Petschek-type configuration that corresponds to the allowable maximum reconnexion rate for the relevant magnetic Reynolds number. We also see that the magnitude of fast reconnexion rate has a weak dependence on the local resistivity in the diffusion region. All our numerical results are very consistent with previous theoretical work on the fast reconnexion problem, once the problem is reconsidered from another angle. We hence suggest that the process of fast reconnexion should be viewed as a gross instability, inherent to the current sheet system itself, that can be triggered by some local onset of anomalous resistivity.