Generation of twist on magnetic flux tubes at the base of the solar convection zone
Generation of twist on magnetic flux tubes at the base of the solar convection zone
复制标题
在太阳对流区底部磁通量管上产生扭曲
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
T. Yokoyama
中科院分区：
文献类型：
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作者：
H. Hotta;T. Yokoyama
利用二维磁流体动力学计算，我们基于 Choudhuri，2003，Sol 的想法，研究了太阳对流区底部磁通量管的扭曲产生机制。 Phys., 215, 31，其中环形磁场被周围的平均极向场包裹。在产生扭曲期间，通量管遵循四个阶段。 (1)它通过涡旋运动迅速分裂成两部分，卷起极向磁场。 (2)由于类似于磁旋转不稳定性的物理机制，卷起的极向场被弯曲和放大。 (3)受扰动的极向磁场的磁张力使涡度减小，涡旋运动引起的升力减小。 (4) 磁通管扭曲并开始再次上升，但没有破裂。对这些过程的研究很重要，因为它表明没有任何初始扭曲的通量管可以在相对较弱的极向场中上升到表面。
Using two-dimensional magnetohydrodynamics calculations, we investigate a twist gen- eration mechanism on a magnetic flux tube at the base of the solar convection zone based on the idea of Choudhuri, 2003, Sol. Phys., 215, 31 in which a toroidal mag- netic field is wrapped by a surrounding mean poloidal field. During generation of the twist, the flux tube follows four phases. (1) It quickly splits into two parts with vortex motions rolling up the poloidal magnetic field. (2) Owing to the physical mechanism similar to that of the magneto-rotational instability, the rolled-up poloidal field is bent and amplified. (3) The magnetic tension of the disturbed poloidal magnetic field re- duces the vorticity, and the lifting force caused by vortical motion decreases. (4) The flux tube gets twisted and begins to rise again without splitting. Investigation of these processes is significant because it shows that a flux tube without any initial twist can rise to the surface in relatively weak poloidal fields.