A ray-tracing analysis of fast-wave heating of tokamaks

Abstract

The complete linear hot-plasma dispersion relation, derived from kinetic theory, is numerically solved for the ion cyclotron range of frequencies. A compact dispersion relation is obtained which is an accurate approximation for both fast and ion Bernstein waves. With the help of this dispersion relation, the three-dimensional ray equations for a tokamak geometry are solved, parabolic density and temperature profiles, the 1/R variation in the toroidal magnetic field, and the resulting poloidal magnetic field due to a rotational transform being incorporated. The ray-tracing analysis is applied to a conceptual design tokamak reactor. The results indicate the nature of the scaling of fast-wave heating to large tokamaks.