Linear studies of m=1 modes in high-temperature plasmas with a four-field model

Abstract

The m=1 mode in high temperature plasmas is examined using a simple four-field model of tokamak dynamics derived by Hazeltine et al. [Phys. Fluids 30, 3204 (1987)]. It is shown that, despite its simplicity, the model reproduces with remarkable accuracy results obtained with more sophisticated kinetic treatments in various collisionality regimes. The effects of parallel compressibility on the m=1 mode in the collisional, semicollisional, and collisionless regimes are also discussed. Coupling to the ion sound waves is found to be weakly destabilizing in the collisional regime, and stabilizing in the semicollisional and collisionless regimes.