Fast-wave current drive modelling for Large non-circular tokamaks

The feasibility of using fast waves to drive substantial toroidal currents is investigated using ray tracing, two-dimensional (2-D) full-wave ICRF modeling and a 2-D code which self-consistently calculates current drive bootstrap current and MHD equilibrium. It is found that n parallel upshifts due to toroidal effects drastically decrease current drive efficiency γ for antennas mounted far off the midplane. With antennas on the midplame, γ ∼ 0.3 to 0.4 should be obtainable. Self-consistent equilibria including bootstrap effect are found in which 18.2 MA of plasma current is driven by 120 MW of RF power: 65 MW of lower hybrid plus 55 MW of fast waves. (author). 4 refs, 2 figs