Ballooning and drift-Alfven modes in tokamaks

Abstract

The magnetohydrodynamic (MHD) ballooning mode in tokamaks was analyzed in the compressible limit. The stability boundary becomes strongly dependent on the toroidicity parameter, εn. This was confirmed by a semilocal kinetic dispersion relation that incorporates kinetic resonances of both ions and electrons. The stability boundary found from the kinetic dispersion relation is insensitive to the degree of plasma compressibility. A nonideal MHD analysis revealed a marginally stable drift-Alfven mode described by [Formula: see text] when βθ (poloidal beta) is of order unity.