A New Physical Mechanism to Account for the “Anomalous Viscosity” in Accretion Disks

Abstract

A new physical mechanism responsible for producing significant radial mass accretion in the inner disk of spiral galaxies has recently been found (Zhang 1996, ApJ, 457, 125). Since this mechanism depends only on the skewness of the global patterns (one-armed or two-armed spiral patterns, as well as skewed central bars) in the underlying disks, and since this process is collective in nature and produces an effective viscosity many orders of magnitude larger than that due to the microscopic processes, it is likely to be an important candidate for the long soughtafter “anomalous viscosity” in many types of astrophysical accretion disks which admit nonaxisymmetric instabilities.