The Radial-Azimuthal Instability of an Isothermal Magnetized Accretion Disk**The project supported by National Natural Science Foundation of China and the National Climbing-Up Programme on Fundamental Research of China

Abstract

The radial-azimuthal instability of an isothermal magnetized accretion disk is examined in this paper. We find that the azimuthal perturbation enhances the instability of the magneto-acoustic and non-axisymmetric modes. The magnetic field induces and enhances the instability of magneto-acoustic modes, but stabilizes the non-axisymmetric modes in the outer disk. The viscous modes are always stable. The instability of magneto-acoustic modes are dominant in this disk.