The isothermal evolution of a shock-filament interaction
The isothermal evolution of a shock-filament interaction
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DOI：
10.1093/mnras/stz3320
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发表时间：
2019-12
影响因子：
4.8
通讯作者：
K. Goldsmith;J. Pittard
中科院分区：
文献类型：
--
作者：
K. Goldsmith;J. Pittard
星际介质中普遍存在的对流结构的研究在许多天体物理领域都具有重要意义。在这里，我们提出了三维流体动力学模拟的冲击细丝相互作用的状态方程已被软化，成为几乎等温。我们调查这样一个等温制度的相互作用（在激波和灯丝是等温的）的效果，我们研究如何相互作用的性质变化时，灯丝的取向，激波马赫数，和灯丝密度对比度是不同的。我们发现，只有横向取向的长丝密度对比度为102形成一个三卷结构，不同于以前的研究结果。此外，细丝的取向角在细丝形态的演变中起着很大的作用：取向角越大，尾流越长且湍流越小。在大多数细丝中，细丝材料的湍流剥离会导致核心碎裂;然而，与激波阵面成85°角的细丝不会碎裂，寿命更长。此外，拖曳时间的值受细丝长度的影响，较长的细丝比较短的细丝加速得更快。此外，在等温状态下的细丝表现出更快的加速度比绝热冲击。最后，我们发现的阻力和混合时间的长丝的取向角增加。
Studies of filamentary structures that are prevalent throughout the interstellar medium are of great significance to a number of astrophysical fields. Here, we present 3D hydrodynamic simulations of shock-filament interactions where the equation of state has been softened to become almost isothermal. We investigate the effect of such an isothermal regime on the interaction (where both the shock and filament are isothermal), and we examine how the nature of the interaction changes when the orientation of the filament, the shock Mach number, and the filament density contrast are varied. We find that only sideways-oriented filaments with a density contrast of 102 form a three-rolled structure, dissimilar to the results of a previous study. Moreover, the angle of orientation of the filament plays a large role in the evolution of the filament morphology: the greater the angle of orientation, the longer and less turbulent the wake. Turbulent stripping of filament material leading to fragmentation of the core occurs in most filaments; however, filaments orientated at an angle of 85° to the shock front do not fragment and are longer lived. In addition, values of the drag time are influenced by the filament length, with longer filaments being accelerated faster than shorter ones. Furthermore, filaments in an isothermal regime exhibit faster acceleration than those struck by an adiabatic shock. Finally, we find that the drag and mixing times of the filament increase as the angle of orientation of the filament is increased.