摘要
本文采用修正的粘滞定律及磁流体力学研究了薄吸积盘内区及外区的稳定性问题，运用微扰方法导出了色散方程，分析了四种情况下吸积盘的不稳定性，结果表明：在同时考虑磁场和修正的粘滞律时，吸积盘中存在着三种振荡模式，其中粘滞模式总是稳定的，磁声速模式（包括向里、向外传播两种模式）通常是不稳定的。这些结果为解释ＢＬＬａｃ天体、Ｓｅｙｆｅｒｔ星系、类星体等活动星系核的光变现象提供了理论依据。
In this paper, we examine the stability of an isothermal accretion disk by using the revised viscosity prescription and MHD equations.By means of dispersion relation, we analyse the instability of the disk in different conditions. We find that the viscous mode is always stable throughout the disk, but the magneto-acoustic modes are pulsationally unstable. The results show that the Mach numbers do effect the instabilities of the disk and the magnetic field enhances the instability property of the radial oscillation. Because the magnetic stress tensor is similar to the viscous stress tensor, the revised viscosity prescription and magnetic field play important roles on the instability of the disk.Our results are useful for understanding the time variations of X-ray stars, BI lac, Seyferts and Quasars.
出处
《天文学报》
CSCD
北大核心
1995年第3期252-260,共9页
Acta Astronomica Sinica
基金
国家攀登计划和国家自然科学基金
