Time Variability of Viscosity Parameters in Differentially Rotating Accretion Disks in Presence of Magnetic Fields

In this research, we tried to study a thin disk in the presence of magnetic field, and then to study the time variability of viscosity parameters as a function of added perturbation factors into the initial conditions of the system. We showed that the time variations of viscosity in each radius have a significant effect in changing thephysical quantities of the disk; such as accretion velocity and surface density which are decreasing as a result of the viscosity growth