Global, Nonaxisymmetric Instabilities in Magnetized Accretion Disks

Abstract We investigate the global stability of a differentially rotating, ideal MHD fluid shell to linear, nonaxisymmetric perturbations. This system, which approximates an accretion disk near its midplane, is known to be unstable to both axisymmetric and nonaxisymmetric local perturbations. Keplerian disks, which are entirely stable in the hydrodynamic case, show the most rapid growth for radially extended shells.