SELF-DESTRUCTING SPIRAL WAVES: GLOBAL SIMULATIONS OF A SPIRAL-WAVE INSTABILITY IN ACCRETION DISKS
SELF-DESTRUCTING SPIRAL WAVES: GLOBAL SIMULATIONS OF A SPIRAL-WAVE INSTABILITY IN ACCRETION DISKS
复制标题
DOI：
10.3847/0004-637x/829/1/13
复制
发表时间：
2016-07
期刊：
影响因子：
--
通讯作者：
J. Bae;R. Nelson;L. Hartmann;S. Richard
中科院分区：
文献类型：
--
作者：
J. Bae;R. Nelson;L. Hartmann;S. Richard
我们提出了一系列三维全局流体动力学模拟的结果，表明在星周盘中传播的螺旋密度波对于参数不稳定性的增长是不稳定的，从而导致流动分解为湍流。这种螺旋波不稳定性 (SWI) 是由成对的惯性波或惯性重力波与背景螺旋波之间的共振相互作用引起的。线性区域不稳定性的发展涉及广泛的惯性模式的增长，其增长速率与轨道时间相当，并导致非线性饱和状态，其中湍流速度扰动与螺旋波引起的扰动具有相似的幅度。湍流引起角动量传输和垂直混合，其速率局部取决于螺旋波的振幅（我们在参考模型中获得应力参数 α ∼ 5 × 10−4 ）。人们发现，这种不稳定性在各种圆盘模型中都存在，包括具有等温或绝热状态方程的模型，以及无量纲运动粘度 ν ≤ 10−5 的粘性圆盘。这种稳健性表明，这种不稳定性将广泛应用于与盘相关的天体物理现象，包括紧密双星系统中的现象、嵌入原行星盘中的行星（包括我们太阳系中的木星）和 FU Orionis 爆发模型。需要进一步的工作来确定不稳定性的性质，并在比我们在本文中考虑的更完整的物理盘模型中评估其观测结果。
We present results from a suite of three-dimensional global hydrodynamic simulations that shows that spiral density waves propagating in circumstellar disks are unstable to the growth of a parametric instability that leads to break down of the flow into turbulence. This spiral wave instability (SWI) arises from a resonant interaction between pairs of inertial waves, or inertial-gravity waves, and the background spiral wave. The development of the instability in the linear regime involves the growth of a broad spectrum of inertial modes, with growth rates on the order of the orbital time, and results in a nonlinear saturated state in which turbulent velocity perturbations are of a similar magnitude to those induced by the spiral wave. The turbulence induces angular momentum transport and vertical mixing at a rate that depends locally on the amplitude of the spiral wave (we obtain a stress parameter α ∼ 5 × 10−4 in our reference model). The instability is found to operate in a wide range of disk models, including those with isothermal or adiabatic equations of state, and in viscous disks where the dimensionless kinematic viscosity ν ≤ 10−5. This robustness suggests that the instability will have applications to a broad range of astrophysical disk-related phenomena, including those in close binary systems, planets embedded in protoplanetary disks (including Jupiter in our own solar system) and FU Orionis outburst models. Further work is required to determine the nature of the instability and to evaluate its observational consequences in physically more complete disk models than we have considered in this paper.