DISCRETE SPECTRUM OF ALFVEN ION-ION HYBRID WAVES

In the Phaedrus-T tokamak [R. Majeski ct al., Phys Fluids B 5, 2506 (1 993)], Alfven waves are indirectly driven by a fast wave antenna array . Small fractions of minority ions can couple Alfven and ion-ion hybri d waves and have a large effect on the wave numbers accessible for a g iven launched frequency. A discrete spectrum and toroidal damping for these modes has been identified by measuring dispersion properties at the edge. Landau damping is predicted to be large and spatially locali zed and to be responsible for the experimentally observed electron hea ting (T. Intrator et al., ''Alfven ion-ion hybrid wave heating in the Phaedrus-T tokamak,'' to appear in Phys. Plasmas) and current drive ne ar the core of the tokamak plasmas. (C) 1996 American Institute of Phy sics.