修正的粘滞律及有磁吸积盘的稳定性研究  

A STUDY OF THE STABILITY IN AN ACCRETION DISK WITH MAGNETIC FIELDS AND A REVISED VISCOSITY PRESCRIPTION

作　　者：吴少平[1] 杨兰田[1] 杨丕博[1] 吴学兵[1] 范秀英[1] 

机构地区：[1]华中师范大学天体物理所,中国科学院北京天文台,湖北十堰大学

出　　处：《天文学报》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

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.

关 键 词：吸积盘 磁流体力学 稳定性 粘滞律 

分 类 号：P145.8[天文地球—天体物理]