The Influence of Hydrodynamical Winds on Hot Accretion Disk Solutions
The Influence of Hydrodynamical Winds on Hot Accretion Disk Solutions
复制标题
水动力风对热吸积盘溶液的影响
DOI：
10.1086/320978
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
R. Taam
中科院分区：
文献类型：
--
作者：
R. Misra;R. Taam
我们研究了可能的流体动力风对热吸积盘溶液性质的影响。我们发现，在有风的情况下，平流主导的分支在温度 θ ∝ 1/r、光学深度 τ ∝ rP-1/2 和吸积率 ∝ rP 的条件下保持圆盘结构的自相似解。根据全球解决方案，风能损失和平流导致的冷却同样重要。对于大范围的粘度和风参数，温度约为维里值的十分之一，P ≈ 0.9，与质量吸积率和半径无关。在通过软光子的不饱和康普顿化进行冷却的背景下，还存在辐射冷却、平流冷却和风冷却很重要的解决方案。在这种情况下，风控解决方案是可能的。这里，临界质量吸积率的径向相关性在其之上不存在解，与没有风的解相比没有变化。风/平流主导的解决方案对于一种称为“风驱动不稳定性”的新型不稳定性局部不稳定，其中风的存在导致圆盘对表面密度的长波长扰动不稳定。这种不稳定性的增长速率与辐射冷却与重力能量耗散率的比率成反比，并且它可以在比盘中的粘性时间尺度长得多的时间尺度上增长，以获得足够小的辐射冷却效率。
We study the effect of a possible hydrodynamical wind on the nature of hot accretion disk solutions. We find that the advection-dominated branch, in the presence of a wind, maintains the self-similar solution for the disk structure with the temperature, θ ∝ 1/r, optical depth, τ ∝ rP-1/2, and accretion rate, ∝ rP. Based on global solutions, cooling due to wind energy loss and advection are found to be equally important. For a wide range of viscosity and wind parameters, the temperature is about one-tenth of the virial value and P ≈ 0.9, independent of the mass accretion rate and radius. In the context of cooling by unsaturated Comptonization of soft photons, solutions also exist in which radiative cooling, advection, and wind cooling are important. In this case, wind-regulated solutions are possible. Here, the radial dependence of the critical mass accretion rate above which solutions do not exist is unchanged from those solutions without winds. The wind/advection-dominated solutions are locally unstable to a new type of instability called "wind-driven instability," in which the presence of a wind causes the disk to be unstable to long-wavelength perturbations of the surface density. The growth rate of this instability is inversely proportional to the ratio of the radiative cooling to the gravitational energy dissipation rates, and it can grow on a timescale much longer than the viscous timescale in the disk for sufficiently small radiative cooling efficiencies.