Three-dimensional magnetohydrodynamics of the emerging magnetic flux in the solar atmosphere
Three-dimensional magnetohydrodynamics of the emerging magnetic flux in the solar atmosphere
复制标题
太阳大气中新兴磁通量的三维磁流体动力学
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
M. Kaisig
中科院分区：
文献类型：
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作者：
R. Matsumoto;T. Tajima;K. Shibata;M. Kaisig
通过三维磁流体动力学模拟，研究了太阳大气中出现的磁通管或磁通片的非线性演化。在初始状态下，假设在磁流体动力学两个等温气体层（近似太阳光球层/色球层和日冕层）的底部嵌入一个水平的磁通量片或磁通量管。磁浮力不稳定性的波动模式对磁通量片或管是不稳定的。由于气体沿沿着磁场线沉淀而增强的浮力所引起的线性和随后的非线性不稳定性，磁回路上升。我们通过三维模拟发现，在磁环上升过程中，通量管束甚至通量片发展成致密的气体细丝，被夹在磁环之间。交换模式有助于在线性阶段中产生垂直于磁场方向的精细纤维通量结构，而波状模式确定整体浮力环结构。这种磁环束的膨胀遵循在先前研究的2D情况下观察到的自相似行为。我们的研究发现，弓丝系统（AFS）形成的阈值通量约为0.3 × 10 - 20 Mx。
The nonlinear evolution of an emerging magnetic flux tube or sheet in the solar atmosphere is studied through 3D MHD simulations. In the initial state, a horizontal magnetic flux sheet or tube is assumed to be embedded at the bottom of MHD two isothermal gas layers, which approximate the solar photosphere/chromosphere and the corona. The magnetic flux sheet or tube is unstable against the undular mode of the magnetic buoyancy instability. The magnetic loop rises due to the linear and then later nonlinear instabilities caused by the buoyancy enhanced by precipitating the gas along magnetic field lines. We find by 3D simulation that during the ascendance of loops the bundle of flux tubes or even the flux sheet develops into dense gas filaments pinched between magnetic loops. The interchange modes help produce a fine fiber flux structure perpendicular to the magnetic field direction in the linear stage, while the undular modes determine the overall buoyant loop structure. The expansion of such a bundle of magnetic loops follows the self-similar behavior observed in 2D cases studied earlier. Our study finds the threshold flux for arch filament system (AFS) formation to be about 0.3 x 10 exp 20 Mx.