Transport of Large Scale Poloidal Flux in Black Hole Accretion

We perform a global, three-dimensional GRMHD simulation of an accretion torus embedded in a large scale vertical magnetic field orbiting a Schwarzschild black hole. This simulation investigates how a large scale vertical field evolves within a turbulent accretion disk and whether global magnetic field configurations suitable for launching jets and winds can develop. We identify a “coronal mechanism” of magnetic flux motion, which dominates the global flux evolution. In this coronal mechanism, magnetic stresses driven by orbital shear create largescale half-loops of magnetic field that stretch radially inward and then reconnect, ar X iv :0 90 6. 27 84 v1 [ as tr oph .H E ] 1 5 Ju n 20 09