Two-dimensional Hydrodynamic Simulations of Convection in Radiation-dominated Accretion Disks
Two-dimensional Hydrodynamic Simulations of Convection in Radiation-dominated Accretion Disks
复制标题
辐射主导吸积盘中对流的二维流体动力学模拟
DOI：
10.1086/322277
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
J. Stone
中科院分区：
文献类型：
--
作者：
E. Agol;J. Krolik;N. Turner;J. Stone
辐射主导的吸积盘的标准平衡长期以来被认为是粘性的、热的和对流的不稳定的，但是这些不稳定性的非线性发展以及这些盘的实际状态还没有被确定。通过对圆盘进行局部二维流体动力学模拟，我们证明了对流运动可以足够迅速地释放热量，从而大大改变圆盘的垂直结构。如果一个垂直圆柱体的耗散率与它的质量成正比，那么这个圆盘就会形成一个新的结构，它比标准的辐射支撑平衡要薄2倍。另一方面，如果垂直积分耗散率与垂直积分总压成正比，则盘受到众所周知的热不稳定性的影响。然而，对流使这种不稳定性的发展偏向于崩溃。这种崩溃的最终结果是在原始柱密度下的气体压力主导的平衡。
The standard equilibrium for radiation-dominated accretion disks has long been known to be viscously, thermally, and convectively unstable, but the nonlinear development of these instabilities—and hence the actual state of such disks—has not yet been identified. By performing local two-dimensional hydrodynamic simulations of disks, we demonstrate that convective motions can release heat sufficiently rapidly as to substantially alter the vertical structure of the disks. If the dissipation rate within a vertical column is proportional to its mass, the disk settles into a new configuration that is thinner than the standard radiation-supported equilibrium by a factor of 2. If, on the other hand, the vertically integrated dissipation rate is proportional to the vertically integrated total pressure, the disk is subject to the well-known thermal instability. Convection, however, biases the development of this instability toward collapse. The end result of such a collapse is a gas-pressure-dominated equilibrium at the original column density.