Rayleigh adjustment of narrow barriers in protoplanetary discs
Rayleigh adjustment of narrow barriers in protoplanetary discs
复制标题
原行星盘窄屏障的瑞利调整
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
K. Menou
中科院分区：
文献类型：
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作者：
Chao;K. Menou
在原行星盘中的尖锐密度特征，例如在磁死区的边缘，最近被提出作为有效的屏障来减缓甚至阻止行星核心向其中心星星的快速迁移。径向尺度上接近圆盘垂直尺度高度的密度特征可能不存在，然而，因为它们可能是瑞利（或更一般的Solberg-Hoiland）不稳定的。在一维粘性吸积盘模型中必须明确地检查稳定性，因为这些不稳定性在减少全套轴对称方程的过程中被人为地消除。盘热力学，通过熵分层，其垂直结构也影响稳定性时，尖锐的密度功能。我们提出了粘性盘模型的瑞利调整的概念：任何密度特征，违反瑞利稳定性（或其推广）应径向扩散的流体动力学湍流的动态时间尺度上，接近边缘稳定性在一个准连续的方式。
Sharp density features in protoplanetary discs, for instance at the edge of a magnetically dead zone, have recently been proposed as effective barriers to slow down or even stop the problematically fast migration of planetary cores into their central star. Density features on a radial scale approaching the disc vertical scaleheight might not exist, however, since they could be Rayleigh (or more generally Solberg-Hoiland) unstable. Stability must be checked explicitly in one-dimensional viscous accretion disc models because these instabilities are artificially eliminated in the process of reducing the full set of axisymmetric equations. The disc thermodynamics, via the entropy stratification, and its vertical structure also influence stability when sharp density features are present. We propose the concept of Rayleigh adjustment for viscous disc models: any density feature that violates Rayleigh stability (or its generalization) should be diffused radially by hydrodynamical turbulence on a dynamical time-scale, approaching marginal stability in a quasi-continuous manner.