Simulation of Buoyant Flux Ropes in a Magnetized Solar Atmosphere
Simulation of Buoyant Flux Ropes in a Magnetized Solar Atmosphere
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磁化太阳大气中浮力磁通绳的模拟
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
P. Cargill
中科院分区：
文献类型：
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作者：
J. Krall;J. Chen;R. Santoro;D. Spicer;S. Zalesak;P. Cargill
利用真实色球和日冕参数研究了重力分层太阳大气中浮力通量绳的动力学。在通量绳上升过程中保持与太阳表面平行的近似条件下，对水平方向通量绳进行了二维磁流体动力学模拟。正如预期的那样，这种运动趋向于在色球-日冕边界处停止，在那里浮力显著下降。结果表明，如果对磁通绳磁场线进行充分扭转，可以减少上升磁通绳分裂成多个磁通束的现象，这与以往的结果一致。研究还表明，微弱的、垂直方向的环境磁场（Ba/Btube）2≪1可以防止未扭曲的磁通管破碎。一个足够强度的垂直场，但仍然“弱”，可以引导向上的浮力驱动的流动，使未扭曲的通量管穿透色球-日冕边界。
Dynamics are investigated for buoyant flux ropes in a gravitationally stratified solar atmosphere using realistic chromosphere and corona parameters. Two-dimensional magnetohydrodynamic simulations of horizontally oriented flux ropes are performed under the approximation that the flux rope remains parallel to the solar surface as it rises. As expected, this motion tends to halt at the chromosphere-corona boundary, where the buoyancy force drops significantly. It is shown that fragmentation of the rising flux rope into multiple flux bundles can be reduced if the flux-rope field lines are sufficiently twisted and that this is consistent with previous results. It is also shown that a weak, vertically oriented ambient magnetic field, (Ba/Btube)2 ≪ 1, can prevent fragmentation of an untwisted flux tube. A vertical field of sufficient strength, but still "weak," can direct the upward buoyancy-driven flow so that the untwisted flux tube penetrates the chromosphere-corona boundary.