Resistive instabilities in a flowing plasma. II. Effects of viscosity

The influence of kinematic viscosity on the properties of resistive instabilities developing in equilibrium configurations in which flows are present is examined. The cross-field viscosity (ν⊥ ) is retained in the linearized resistive magnetohydrodynamic equations, which are solved numerically. The magnetic and velocity equilibrium configurations are the same as those studied in a previous paper [Phys. Fluids 29, 2563 (1986)] neglecting viscosity, so that its effect can be easily studied in the present work. The results show that the inclusion of the viscosity changes the stability properties considerably when τν≤τr, and where τν and τr are the viscous and magnetic time scales, respectively. Depending on the relative importance of the velocity with respect to the Alfvén velocity and of the velocity scale length with respect to the magnetic one, the viscosity can have both a stabilizing and a destabilizing effect.