含三维磁场等温薄吸积盘的振荡不稳定性

The Oscillatory Instability of an Isothermal Disc with a Three Dimensional Magnetic Field

本文从磁流体动力学方程组出发，用微扰法得出含三维磁场等温薄吸积盘的径向、轴向及环向不稳定性的色散方程．并详细讨论了磁场各分量对吸积盘不稳定性的影响．结果表明，磁场的径向和环向分量对磁声模和非轴对称模的不稳定性的增加起着主要的作用，且径向振荡大于轴向振荡．

The dispersion equation for radial, axial and azimuthal instabilities of an isothermal disc with a three dimensional magnetic field is derived by the perturbation method. The effects of the different field components are discussed in detail. We find that the radial and azimuthal fields B r, B  are mainly responsible for enhancing the instability of the magneto acoutic modes and non axisymmetric modes, and that pulsational oscillations are larger in the radial than in the Z direction. The model may be useful in explaining the periodic light variations of FU orionis and T Tauri Stars.