Effects of Fluid Instabilities on Accretion Disk Spectra

Numerical calculations and linear theory of radiation magnetohydrodynamic flows indicate that the photon bubble and magnetorotational instability (MRI) may produce large density inhomogeneities in radiation pressure supported media. We study the effects of the photon bubble instability on accretion disk spectra using 2-D Monte Carlo (MC) and 1-D Feautrier radiative transfer calculations on a snapshot of a 2-D numerical simulation domain. We find an enhancement in the thermalization of the MC spectra over that of the Feautrier calculation. In the inner-most regions of these disks, the turbulent magnetic pressure may greatly exceed that of the gas. It is then possible for bulk turbulent Alfvenic motions driven by the MRI to exceed the thermal velocity making turbulent Comptonization the dominant radiative process. We estimate the spectral distortion due to turbulent Comptonization utilizing a 1-D MC calculation.