含粘滞的弱磁化吸积盘的轴对称脉动不稳定性

The Axisymmetric Pulsational Instability in Weakly Magnetized Accretion Disks with Viscosity

讨论了一种含扩散型粘滞的弱磁化等温吸积盘模型，在此模型中研究了扩散型粘滞和垂向磁场ＢＺ，环向磁场Ｂ对轴对称脉动不稳定性的影响．结果表明：对于轴对称扰动，一般情况下吸积盘内存在４种轴对称振荡模式，其中２种模式（对应于）是脉动不稳定的，扩散型粘滞及磁场ＢＺ，Ｂ对它们表现为非稳因素；而另外２种模式（对应于）是稳定的．此外．仅当同时存在ＢＺ和Ｂ时，磁场才能影响这些振荡模式的不稳定性．

A model of weakly magnetized, isothermal accretion disks with viscosity isinvestigated in this paper. The influences of diffusion-type viscosity, and the vertical magnetic,field and the azimuthal magnetic field on the axisymmetric pulsational instability in this model arediscussed. It is shown that there exist four modes of axisymmetric oscillations in the disks,arising from the axisymmetric perturbations. Only when both the vertical magnetic field and theazimuthal magnetic field are present can they affect the instability of these oscillation modes.Two of these modes (correspond to ) are always pulsational instable, and the other twomodes (correspond to ) are always stable. These results are of great advantage to theexplanation of the luminosity variation of the active astronomical objects.