Design constraints for steady-state tokamak reactors driven by lower hybrid waves

Abstract

Plasma current density profiles are computed with the inclusion of electron Landau damping of lower hybrid waves launched into model tokamak density and temperature profiles. The total current and current profile shape are chosen consistent with magnetohydrodynamic equilibrium for a variety of temperature and density distributions and plasma beta values. Surface current equilibria appear attractive and are accessible to waves with nz as low as 1.2. By suitably choosing the spectrum location and width it is possible to drive the 9.8-MA current of a 7.0-m reactor with as little as 2.8% of the fusion power re-circulated as RF input from the waveguides.