Magnetic Reconnection in MHD Turbulence in Accretion Disks

Takayoshi Sano

MHD turbulece driven by the magnetorotational instability (MRI) is the
most promising mechanism of anglar momentum transport in accretion
disks.  The saturation amplitude of the magnetic field gives the
efficiency of angular momentum transport.  Magnetic reconnection is
one of the key processes to determine the saturation.  We investigate
magnetic reconnection in MHD turbulence in accretion disks using
multi-dimensional MHD simulatoins.  The most unstable mode of the MRI,
which is called a channel flow, produces a current sheet with shear
motions.  We found that the reconnection is triggered by
Kelvin-Helmholtz instability or tearing instability after the
nonlinear growth of the channel flow.  We will discuss the role of
magnetic reconnection in determining the saturation level of the MRI.