ALFVEN ION-ION HYBRID WAVE HEATING IN THE PHAEDRUS-T TOKAMAK

In the Phaedrus-T tokamak [R. A. Breun et al., Fusion Technol. 19, 132 7 (1991)], Alfven waves are indirectly driven by a fast wave antenna a rray. Small fractions of minority ions are shown to have a large effec t on the Alfven spectrum, as measured at the edge. An ion-ion hybrid A lfven mode has been identified by measuring dispersion properties. Lan dau damping is predicted to be large and spatially localized. These Al fvenic waves are experimentally shown to generate correlated electron heating and changes in density near the core of the tokamak plasma. Fa st wave antenna fields can mode convert at a hybrid Alfven resonance a nd provide a promising route to spatially localized tokamak heating an d current drive, even for low effective ionic charge Z(eff)approximate to 1.3-2. (C) 1996 American Institute of Physics.