Time: Oct. 8th; 2:00PM

Location: Middle Conference Room, 3rd floor

Speaker: Dr. Xiaoyue Guan (University of Virginia)

Abstract:

Magnetohydrodynamical (MHD) turbulence induced by magnetorotational instability (MRI) is the most promising candidate for driving angular momentum transport in accretion disks. Numerical simulation of MHD turbulent disks makes it possible to study accretion process in detail. In this talk, I will first discuss recent results from local shearing-box studies, concentrating on the turbulence saturation level, disk vertical structure and existence of quasi-periodic oscillations. I will then present new global black hole thin disk simulations in full general relativity, highlighting the issue of inner disk stress in the context of Novikov-Thorne model. Global simulations are starting to resolve the MRI-induced turbulence structure in the disk and I will compare some results derived from the local and global thin disk simulations.