Secondary tearingmode in the nonlinear evolution of magnetorotational instability

Numerical investigation of the two-dimensional magnetic reconnection is given in the context of the nonlinear evolution of the Magneto-Rotational Instability (MRI). With a careful comparison to various theories using both one- and twodimensional analysis, it is found that a new stabilizing effect of the centrifugal force on tearing instability must be present in the specific geometry of the MRI.Magnetic reconnection might play a key role to the formation of the nonaxisymmetric structures observed in MRI experiments. The results may also be useful for the estimate of the accretion rate in various astrophysical objects. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)