含粘滞性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

作　　者：汪定雄[1] 杨兰田[2] 

机构地区：[1]中南民族学院物理系,华中理工大学物理系武汉430074 [2]华中师范大学天体物理研究所,武汉430070

出　　处：《天文学报》1997年第1期48-55,共8页Acta Astronomica Sinica

基　　金：国家自然科学基金;国家攀登计划资助

摘　　要：本文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、垂向磁场Bz和环向磁场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，一般情况下盘内存在四种轴对称振荡模式．其中二种模式是脉动不稳定的，粘滞和磁场对它们表现为非稳因素；而另外二种模式是稳定的，粘滞和磁场对它们表现为致稳因素．此外我们还注意到，Bz和B主要影响近轴向的脉动不稳定性，扩散型弱粘滞主要影响径向脉动不稳定性．model of weakly magnetized, isothermal accretion disks with viscosity is investigated in this paper.The influences of the diffusion-type viscosity, vertical magnetic field and azimuthal magnetic field on the axisymmetric pulsational instability in this model are discussed.It is shown that there exist four modes of axisymmetric oscillations in the disks, arising from the axisymmetric perturbations.Two of these modes are always pulsationally unstable, and the viscosity and the magnetic fields act as factors of instability.The other two modes are always stable, and the viscosity and the magnetic fields are stabilizing factors.In addition, we find that the nearly axial pulsational instability is affected mainly by the magnetic fields Bz and B, while the radial pulsational instability is affected mainly by the diffusion-type viscosity.

关 键 词：吸积盘 磁流体动力学 不稳定性 磁化 扩散型粘滞 

分 类 号：P145.8[天文地球—天体物理]