Structure and Evolution of Global Accretion Disk Simulations

We present Athena++ global three-dimensional magneto-hydrodynamic simulations of accretion flows onto stellar mass black holes for several accretion rates from about 0.1 to nearly Eddington. We focus on the potential emergence of a hot corona powered by significant dissipation near the disk photospheres. We also investigate time evolution and variability in our calculations paying particular attention to potential sources of quasi-periodic oscillations. Finally, we discuss the implications of results for steep power law spectral state observations.