Instability of anomalous viscosity disks around young stellar objects

An accretion disk with vertical structure around a young stellar object is investigated, considering anomalous magnetic viscosity. It was found that the I-mode was unstable in the outer disk, and sometimes turned stable in the inner disk, for the standard α model. However, we find that the I-mode is always unstable in the inner disk, owing to the anomalous magnetic viscosity.