CONSERVATIVE GRMHD SIMULATIONS OF MODERATELY THIN, TILTED ACCRETION DISKS
CONSERVATIVE GRMHD SIMULATIONS OF MODERATELY THIN, TILTED ACCRETION DISKS
复制标题
中等厚度、倾斜吸积盘的保守 GRMHD 模拟
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
P. Ivanov
中科院分区：
文献类型：
--
作者：
D. M. Teixeira;P. C. Fragile;V. Zhuravlev;P. Ivanov
本文给出了我们最新的关于相对于克尔黑洞旋转轴错位的吸积盘的数值模拟。在这项工作中，我们使用了宇宙++广义相对论磁流体动力学(GRMHD)程序的一个新的、完全保守的版本，加上一个专门设计的冷却功能来控制盘的厚度。综合起来，我们可以用GRMHD程序模拟最薄的倾斜吸积盘。通过这种方式，我们能够探索无量纲应力和圆盘标度高度具有可比性的区域。我们给出了进行性和逆行性病例的结果。模拟的前倾盘没有显示Bardeen-Petterson排列的迹象，即使在盘的最里面部分也是如此。然而，模拟的逆行倾斜的椎间盘确实显示出适度的对准。这些结果表明，对于递进圆盘，与Bardeen-Petterson排列相关的参数空间可能相当小，仅包括非常薄的圆盘。与我们之前的工作不同，我们在模拟的倾斜圆盘中没有发现站立震荡的证据。我们将其归因于黑洞自转、倾角和盘尺度高度在这些模拟中都很小。我们还补充了越来越多的文献，指出在全球吸积盘模拟中，由磁旋转不稳定性驱动的湍流不是各向同性的。最后，我们给出了我们的中等厚度、无约束的参考模拟与文献中其他薄盘的数值模拟的比较。
This paper presents our latest numerical simulations of accretion disks that are misaligned with respect to the rotation axis of a Kerr black hole. In this work, we use a new, fully conservative version of the Cosmos++ general relativistic magnetohydrodynamics (GRMHD) code, coupled with an ad hoc cooling function designed to control the thickness of the disk. Together these allow us to simulate the thinnest tilted accretion disks ever using a GRMHD code. In this way, we are able to probe the regime where the dimensionless stress and scale height of the disk become comparable. We present results for both prograde and retrograde cases. The simulated prograde tilted disk shows no sign of Bardeen–Petterson alignment even in the innermost parts of the disk. The simulated retrograde tilted disk, however, does show modest alignment. The implication of these results is that the parameter space associated with Bardeen–Petterson alignment for prograde disks may be rather small, only including very thin disks. Unlike our previous work, we find no evidence for standing shocks in our simulated tilted disks. We ascribe this to the black hole spin, tilt angle, and disk scale height all being small in these simulations. We also add to the growing body of literature pointing out that the turbulence driven by the magnetorotational instability in global simulations of accretion disks is not isotropic. Finally, we provide a comparison between our moderately thin, untilted reference simulation and other numerical simulations of thin disks in the literature.