Topological evolution of Parker-unstable galactic magnetic fields under the influence of Coriolis force and magnetic reconnection
Topological evolution of Parker-unstable galactic magnetic fields under the influence of Coriolis force and magnetic reconnection
复制标题
科里奥利力和磁重联影响下帕克不稳定星系磁场的拓扑演化
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发表时间：
2002
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影响因子：
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通讯作者：
H. Lesch
中科院分区：
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作者：
M. Hanasz;K. Otmianowska;H. Lesch
研究了科里奥利力和磁场重联对银盘中帕克不稳定性演化的影响。我们应用一个局部气体立方体的模型，通过一个方位角的大规模磁场渗透和数值求解电阻三维磁流体力学方程，包括科里奥利力的贡献。我们引入了一个依赖于电流的电阻率开关的磁重联高于一定的临界电流密度。我们研究了磁场拓扑结构的演化和大尺度极向磁场从初始方位场的形成。我们的模拟表明，帕克不稳定性导致形成的螺旋扭曲的磁通量管，然后通过磁重联形成，一个显着的极向磁场分量上的整个立方体的规模团聚。这种演变代表了一种快速发电机过程，如帕克（1992，ApJ 401，137）所提出的。
We investigate the influence of the Coriolis force and magnetic reconnection on the evolution of the Parker instability in galactic disks. We apply a model of a local gas cube, permeated by an azimuthal large-scale magnetic field and solve numerically resistive 3D MHD equations including the contribution of the Coriolis force. We introduce a current-dependent resistivity which switches the magnetic reconnection above a certain critical current density. We study the evolution of the magnetic field topology and the formation of large-scale poloidal magnetic fields from the initial azimuthal field. Our simulations demonstrate that the Parker instability leads to the formation of helically twisted magnetic flux tubes which are then agglomerated by magnetic reconnection forming, a significant poloidal magnetic field component on the scale of the whole cube. Such an evolution represents a kind of fast dynamo process as proposed by Parker (1992, ApJ 401, 137).