Dissipation Triggers Dynamical Two-Stream Instability
Dissipation Triggers Dynamical Two-Stream Instability
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DOI：
10.3390/particles2040028
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发表时间：
2019-08
期刊：
影响因子：
1.4
通讯作者：
N. Andersson;A. Schmitt
中科院分区：
文献类型：
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作者：
N. Andersson;A. Schmitt
两个耦合，互穿流体遭受超过某些临界逆流的不稳定性。对于理想流体，能量不稳定性发生在声音模式由于逆流而反转其方向的点处，而动力学不稳定性仅发生在较大的相对速度下。在这里，我们讨论两种相对论流体，其中之一是耗散。使用线性流体力学，我们表明，在这种情况下，充满活力的不稳定性变成动态的，即，存在指数增长模式，并且这种指数增长仅在存在耗散的情况下发生。这个结果是普遍的，并不依赖于一个潜在的微观理论。它可以应用于各种双流体系统，例如，在中子星的内部。我们还指出，在某些情况下，双流体系统表现出一种模式类似于中子星的r-模式，可以成为不稳定的任意小的值的逆流。
Two coupled, interpenetrating fluids suffer instabilities beyond certain critical counterflows. For ideal fluids, an energetic instability occurs at the point where a sound mode inverts its direction due to the counterflow, while dynamical instabilities only occur at larger relative velocities. Here, we discuss two relativistic fluids, one of which is dissipative. Using linearized hydrodynamics, we show that, in this case, the energetic instability turns dynamical, i.e., there is an exponentially growing mode, and this exponential growth only occurs in the presence of dissipation. This result is general and does not rely on an underlying microscopic theory. It can be applied to various two-fluid systems, for instance, in the interior of neutron stars. We also point out that, under certain circumstances, the two-fluid system exhibits a mode analogous to the r-mode in neutron stars that can become unstable for arbitrarily small values of the counterflow.