Prof Steven Balbus FRS, FInstP

Abstract:

A long-standing problem in the theory of astrophysical accretion disks has been to determine the nature of the stress that transports orbital angular momentum outward. The recent discovery of a local MHD instability provides strong evidence that transport is through turbulent Maxwell and Reynolds stresses. Using numerical simulations we have demonstrated that a weak seed magnetic field in an accretion disk is unstable and leads to sustained MHD turbulence at dynamically important levels. The accretion disk provides a natural laboratory for the study of MHD turbulence.