Simulation Study of the Formation Mechanism of Sigmoidal Structure in the Solar Corona
Simulation Study of the Formation Mechanism of Sigmoidal Structure in the Solar Corona
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DOI：
10.1086/432570
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发表时间：
2005-10
期刊：
影响因子：
--
通讯作者：
K. Kusano
中科院分区：
文献类型：
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作者：
K. Kusano
基于Kusano等人最近提出的反向剪切耀斑模型，利用三维磁流体动力学数值模拟研究了日冕磁场中S形结构的形成机制.模拟结果清楚地表明，由磁剪切反转层上的电阻撕裂模不稳定性所驱动的磁场重联可以导致S形结构的自发形成.此外，它也是数字表明，形成的S形可以遵循的爆炸能量释放，如果S形包含足够的磁通量。这意味着，反向剪切耀斑模型可以提供一个自洽的解释形成的S形以及爆发的开始，这是由磁重联以上的S形驱动。S形结构与J. B预测的最低能态之间的几何关系。泰勒在1974年被审查。结果表明，S形结构可以理解为最小能态的一种表现，与线性无力场的分岔判据相比，它具有过剩的磁螺旋度.文中还讨论了与磁螺度观测的一致性。
The formation mechanism of sigmoidal structure in the solar coronal magnetic field is studied using the three-dimensional magnetohydrodynamic numerical simulations, based on the so-called reversed-shear flare model recently proposed by Kusano et al. The simulation results clearly indicate that magnetic reconnection driven by the resistive tearing mode instability growing on the magnetic shear inversion layer can cause the spontaneous formation of sigmoidal structure. Furthermore, it is also numerically demonstrated that the formation of the sigmoids can be followed by the explosive energy liberation, if the sigmoids contain sufficient magnetic flux. This implies that the reversed-shear flare model can provide a self-consistent explanation for the formation of sigmoids as well as for the onset of eruption, which is driven by magnetic reconnection above sigmoids. The geometric relationship between the sigmoidal structure and the minimum energy state predicted by J. B. Taylor in 1974 is examined. The result suggests that the sigmoidal formation could be understood as a manifestation of the minimum energy state, which has the excess magnetic helicity compared to the bifurcation criterion of the linear force-free field. The consistency with the observations of magnetic helicity is also discussed.