Coupling between internal waves and shear-induced turbulence in stellar radiation zones: the critical layers
Coupling between internal waves and shear-induced turbulence in stellar radiation zones: the critical layers
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恒星辐射区内波与剪切引起的湍流之间的耦合：关键层
DOI：
10.1051/0004-6361/201321210
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发表时间：
2013
影响因子：
6.5
通讯作者：
T. Decressin
中科院分区：
文献类型：
--
作者：
L. Alvan;S. Mathis;T. Decressin
由于重力内波在角动量输运中的重要作用，它被认为是解释太阳、太阳型主序星和演化恒星角速度分布的候选者之一。我们带来的关注临界层，一个在恒星物理学中很少探索的过程，定义为给定波的局部相对频率与流体旋转频率趋于零的位置（即对应于共旋转共振）。IGW传播通过稳定分层的辐射区域，在那里它们通过两个过程提取或存款角动量：辐射和粘性阻尼和临界层。我们的目标是全面了解后者的影响。首先，我们揭示了IGWs在绝热和非绝热情况下的临界层附近的传播方程的数学解决方案。然后，使用一个动态恒星演化代码，它处理的长期运输的角动量，使我们能够应用这些结果的情况下，类似太阳的星星。分析揭示了两种情况下，取决于理查森数的值在关键层：一个稳定的，IGW衰减，因为他们通过一个临界水平，以及不稳定的湍流情况，其中它们可以被具有大于1的系数的临界水平反射/透射。这种过度反射/透射可能对我们对恒星内部角动量输运的看法产生强烈的影响。本文强调存在两个制度定义IGW和临界层之间的相互作用。一个应用程序暴露的第一个政权的效果，表现出加强波的阻尼。此外，这项工作开辟了新的途径有关IGW和恒星内部剪切不稳定性之间的耦合。
Internal gravity waves (hereafter IGWs) are known as one of the candidates for explaining the angular velocity profile in the Sun and in solar-type main-sequence and evolved stars, due to their role in the transport of angular momentum. Our bringing concerns critical layers, a process poorly explored in stellar physics, defined as the location where the local relative frequency of a given wave to the rotational frequency of the fluid tends to zero (i.e that corresponds to co-rotation resonances). IGW propagate through stably-stratified radiative regions, where they extract or deposit angular momentum through two processes: radiative and viscous dampings and critical layers. Our goal is to obtain a complete picture of the effects of this latters. First, we expose a mathematical resolution of the equation of propagation for IGWs in adiabatic and non-adiabatic cases near critical layers. Then, the use of a dynamical stellar evolution code, which treats the secular transport of angular momentum, allows us to apply these results to the case of a solar-like star.The analysis reveals two cases depending on the value of the Richardson number at critical layers: a stable one, where IGWs are attenuated as they pass through a critical level, and an unstable turbulent case where they can be reflected/transmitted by the critical level with a coefficient larger than one. Such over-reflection/transmission can have strong implications on our vision of angular momentum transport in stellar interiors. This paper highlights the existence of two regimes defining the interaction between an IGW and a critical layer. An application exposes the effect of the first regime, showing a strengthening of the damping of the wave. Moreover, this work opens new ways concerning the coupling between IGWs and shear instabilities in stellar interiors.
太阳型恒星中心附近的内波破碎和潮汐耗散
DOI：
10.1111/j.1365-2966.2010.16400.x
发表时间：
2010
影响因子：
4.8
作者：
Barker A
通讯作者：
Barker A