论文标题
天体物理盘的本地模型中的扭曲的流体动力学
Hydrodynamics of warps in the local model of astrophysical discs
论文作者
论文摘要
我们展示了天体物理盘的局部近似是如何使用剪切盒的著名模型的基础来研究翘曲盘动力学的许多方面。在本地模型中，相对于参考轨道的轨道倾斜对应于轨道频率下粒子的垂直振荡。圆盘的翘曲对应于椎间盘中间平面的局部轴对称波纹，该圆盘的中平面在轨道频率下垂直振荡，而经线的演变则对应于垂直振荡复合幅度的调节。我们为这种幅度得出了保护法，这是局部等同于保护角动量的局部幅度，因此控制了翘曲的演变。对于与椎间盘的垂直尺度相比，长度长的长度尺度，已知的扭曲动力学的非谐振和谐振机制（包括开普勒碟片的扩散和波动状态）以与全球旋转碟片视图相同的方式出现在局部模型中。
We show how the local approximation of astrophysical discs, which is the basis for the well known model of the shearing box, can be used to study many aspects of the dynamics of warped discs. In the local model, inclination of the orbit of a test particle with respect to the reference orbit corresponds to a vertical oscillation of the particle at the orbital frequency. Warping of a disc corresponds to a locally axisymmetric corrugation of the midplane of the disc that oscillates vertically at the orbital frequency, while evolution of the warp corresponds to a modulation of the complex amplitude of the vertical oscillation. We derive a conservation law for this amplitude that is the local equivalent of the conservation of angular momentum and therefore governs the evolution of the warp. For lengthscales that are long compared to the vertical scaleheight of the disc, the known non-resonant and resonant regimes of warp dynamics, including the diffusive and wavelike regimes of Keplerian discs, occur in the local model in the same way as in a global view of warped discs.
