Institute for Advanced Study Astrophysics Seminar

ABSTRACT: Studies of a variety of gas dynamical problems, for example the saturation of the MRI in the inner regions of accretion disks around compact objects, or the effects of feedback from starbursts and/or AGN, require numerical algorithms for radiation magnetohydrodynamics (MHD). A new method which relaxes some of the restrictive assumptions of previous approaches will be described. The method is currently being used for a variety of applications, and preliminary results from these studies will be presented. In particular, motivated by the problem of radiation feedback, we present initial studies of the nonlinear evolution of the Rayleigh-Taylor instability in radiation-supported atmospheres, and the ablation of dense clumps in the ISM by radiation. In addition, new studies of the saturation amplitude of the MRI in radiation dominated disks using the local shearing box approximation will be described.