Magnetohydrodynamic Simulations of Shock Interactions with Radiative Clouds
Magnetohydrodynamic Simulations of Shock Interactions with Radiative Clouds
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DOI：
10.1086/426313
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发表时间：
2004-10
期刊：
影响因子：
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通讯作者：
P. C. Fragile;P. Anninos;K. Gustafson;Stephen D. Murray
中科院分区：
文献类型：
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作者：
P. C. Fragile;P. Anninos;K. Gustafson;Stephen D. Murray
我们提出的结果从二维数值模拟磁化冲击和辐射云之间的相互作用。我们的主要目标是描述冲击云的动力学演化。我们在强磁场和弱磁场的限制下运行，并考虑三种不同的磁场方向。对于所考虑的几何形状，我们通常发现，外部的磁场，但集中在附近，云的表面抑制破坏性的流体动力学不稳定性的增长。外部场也通过有效地充当由星际流和局部场拉伸驱动的约束机制来增加云的压缩。这可能对辐射冷却的效率（随着磁场强度的增加而增加）和冷凝冷却碎片的大小和分布产生巨大影响。相反，主要作用于云内部的场往往抵抗压缩，从而抑制冷却。我们观察到，即使在中等强度（β0 ~ 100），内部场可以完全抑制二维云的低温（T < 100 K）冷却。
We present results from two-dimensional numerical simulations of the interactions between magnetized shocks and radiative clouds. Our primary goal is to characterize the dynamical evolution of the shocked clouds. We perform runs in both the strong and weak magnetic field limits and consider three different field orientations. For the geometries considered, we generally find that magnetic fields external to, but concentrated near, the surface of the cloud suppress the growth of destructive hydrodynamic instabilities. External fields also increase the compression of the cloud by effectively acting as a confinement mechanism driven by the interstellar flow and local field stretching. This can have a dramatic effect on both the efficiency of radiative cooling, which tends to increase with increasing magnetic field strength, and on the size and distribution of condensed cooled fragments. In contrast, fields acting predominately internally to the cloud tend to resist compression, thereby inhibiting cooling. We observe that, even at modest strengths (β0 ≲ 100), internal fields can completely suppress low-temperature (T < 100 K) cooling in two-dimensional clouds.