The interaction of a magnetohydrodynamical shock with a filament
The interaction of a magnetohydrodynamical shock with a filament
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DOI：
10.1093/mnras/stw1365
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发表时间：
2016-07
影响因子：
4.8
通讯作者：
K. Goldsmith;J. Pittard
中科院分区：
文献类型：
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作者：
K. Goldsmith;J. Pittard
我们对激波与致密丝状云的绝热相互作用进行了3D磁流体动力学数值模拟。我们研究了不同的灯丝长度和方向对相互作用的影响，使用不同的磁场方向，并改变激波的马赫数，密度对比的灯丝χ，和等离子体β，以确定其对灯丝的演变和寿命的影响。我们发现，在一个平行的磁场细丝有更长的寿命，如果他们的取向更“宽边”的冲击波阵面，并在χ的增加加速云的破坏，在修改后的云粉碎的时间尺度，TCS。温和的冲击和垂直或倾斜的磁场的组合为延长灯丝的寿命提供了最佳条件，一些灯丝几乎可以无限期地存活，因为它们被磁场包围。在垂直场或斜场的情况下，高的χ值不会引起大的湍流不稳定性，而是将细丝拉成长的卷须，最终可能碎裂。此外，磁通绳仅在平行磁场中形成。然而，细丝的长度对于细丝的演化和破坏并不重要。
We present 3D magnetohydrodynamic numerical simulations of the adiabatic interaction of a shock with a dense, filamentary cloud. We investigate the effects of various filament lengths and orientations on the interaction using different orientations of the magnetic field, and vary the Mach number of the shock, the density contrast of the filament χ, and the plasma beta, in order to determine their effect on the evolution and lifetime of the filament. We find that in a parallel magnetic field filaments have longer lifetimes if they are orientated more ‘broadside’ to the shock front, and that an increase in χ hastens the destruction of the cloud, in terms of the modified cloud-crushing time-scale, tcs. The combination of a mild shock and a perpendicular or oblique field provides the best condition for extending the life of the filament, with some filaments able to survive almost indefinitely since they are cocooned by the magnetic field. A high value for χ does not initiate large turbulent instabilities in either the perpendicular or oblique field cases but rather draws the filament out into long tendrils which may eventually fragment. In addition, flux ropes are only formed in parallel magnetic fields. The length of the filament is, however, not as important for the evolution and destruction of a filament.