ABSTRACT
This chapter explores the ideal modes modified by the viscosity that is the so-called ideal–viscous modes. It suggests that for a sufficiently high viscosity these modes are changed by the so-called viscous-resistive ballooning modes. Their growth rate is small compared with that of the ideal–viscous ballooning instability. In the presence of the viscosity, new modes appear. A sufficiently high viscosity leads to stabilization of both the inertial and the inertialess modes. The viscous instabilities are of more interest in the case of a finite-pressure plasma than the non-viscous instabilities. The fact that the longitudinal viscosity can be important in the problem of magnetohydrodynamic modes in a toroidal plasma. The chapter examines the role of the viscosity in resistive kink modes.
