Outgoing and Global Drift Waves in Rotating Toroidal Plasma Configuration

Abstract

The drift waves in rotating toroidal plasma are studied for an axisymmetric, large-aspect-ratio tokamak with concentric and circular magnetic surfaces. Plasma rotation is driven by the radial electrostatic field typical for the H confinement mode of plasma in tokamaks. Low-frequency electrostatic oscillations of low-beta plasma are considered in assumptions of adiabatic electrons and plasma quasineutrality. In order to describe drift oscillations in the plasma edge region, where the radial electric field and plasma rotation velocity are high, a weak coupling approximation that takes into account the toroidal coupling of normal modes centred on the neighbouring rational surfaces is considered. The derived eigenmode equation of the Weber type has two classes of solutions giving either marginally stable global drift modes or propagating drift waves which experience shear damping. The analytical dispersion equations, for both global and propagating drift waves are derived and the simple dispersion relations for some limiting cases are determined.