论文标题
带冷却的原星盘的Rossby波浪不稳定性
Rossby Wave Instabilities of Protoplanetary Discs with Cooling
论文作者
论文摘要
Rossby波浪不稳定性（RWIS）通常会导致原球盘中的非轴对称涡旋，并且RWI可以很好地解释这些光盘的一些观察到的子结构。我们探索冷却如何根据线性扰动分析影响不稳定的RWI模式的增长率。与能量方程相关的冷却以两种不同的方式处理。我们采用的第一个是简单的冷却定律。扰动的热状态在规定的冷却时间尺度上放松到最初的热状态。第二，我们将冷却视为热扩散过程。对于声速较小的光盘，绝热模式和等温模式之间的生长速率的差异变得更加明显。对于简单的冷却定律，不稳定模式的增长速率随着压缩光盘的较短冷却时间尺度而单调降低。但是，在非碳圆盘中，生长速率与冷却时间尺度的依赖性成为非单调的。在从绝热状态到等温状态的过渡期间，在非 - 芳香族光盘中甚至可能会增强RWI。当将冷却视为热扩散，即使在正压盘中，随着热扩散率的生长速率变化也会成为非单调的。此外，最大生长速率可能以适当的热扩散率值出现。研究了角动量通量（AMF），以了解RWI通过冷却来了解RWI的角动量转运。
Rossby wave instabilities (RWIs) usually lead to nonaxisymmetric vortices in protoplanetary discs and some observed sub-structures of these discs can be well explained by RWIs. We explore how the cooling influences the growth rate of unstable RWI modes in terms of the linear perturbation analysis. The cooling associated with the energy equation is treated in two different ways. The first one we adopt is a simple cooling law. The perturbed thermal state relaxes to the initial thermal state on a prescribed cooling timescale. In the second, we treat the cooling as a thermal diffusion process. The difference in the growth rate between the adiabatic and isothermal modes becomes more pronounced for discs with smaller sound speed. For the simple cooling law, the growth rates of unstable modes monotonically decrease with the shorter cooling timescale in barotropic discs. But the dependence of growth rate with the cooling timescale becomes non-monotonic in non-baratopic discs. The RWI might even be enhanced in non-barotropic discs during the transition from the adiabatic state to the isothermal state. When the cooling is treated as the thermal diffusion, even in barotropic disc, the variation of growth rate with thermal diffusivity becomes non-monotonic. Further more, a maximum growth rate may appear with an appropriate value of thermal diffusivity. The angular momentum flux (AMF) is investigated to understand the angular momentum transport by RWI with cooling.
