LOWER HYBRID RF HEATING EXPERIMENTS IN THE MIT ALCATOR-A, ALCATOR-C AND VERSATOR II TOKAMAKS*

ABSTRACT Experimental results on lower hybrid heating in the Alcator A and the Versator II tokamaks with power levels up to 90 kW are presented. In Alcator A a double waveguide grill, and in Versator II a 4 waveguide grill with arbitrary phasing are used. Also, a 6 waveguide grill experiment in Versator II is described which launches a travelling wave aimed at driving toroidal currents. The. forthcoming lower hybrid heating experiment in Alcator C, utilizing four 4×4 waveguide arrays with power levels up to 4 MW, is also described.