DIAGNOSTICS OF ION CYCLOTRON HEATED TOKAMAK PLASMAS

DURING FAST WAVE MINORITY AND SECOND HARMONIC HEATING OF TOKAMAKS, THE MAGNETIC AXIS SHIFTS OUTWARD WITH RESPECT TO THE RESONANCE LAYER CAUSED BY THE INCREASING PRESSURE. BY ADJUSTING THE VERTICAL OR TOROIDAL MAGNETIC FIELD, THE MAGNETIC AXIS CAN BE MAINTAINED NEAR THE OPTIMUM LOCATION WITH RESPECT TO THE RESONANCE LINE. IN PHASE I, THE PRELIMINARY WORK IS BEING PERFORMED TO DETERMINE THIS OPTIMUM LOCATION BY INTEGRATING THE RESULTS OF EXISTING DIAGNOSTICS AND THE QUASILINEAR FORMALISM RECENTLY DEVELOPED. BECAUSE OF THE HIGHLY ANISOTROPIC NATURE OF THE RADIO FREQUENCY (RF) HEATED SPECIES, AN IMPROVED TREATMENT IS NECESSARY TO PROPERLY INTERPRET EXISTING DIAGNOSTICS OF THE RF POWER ABSORPTION PROFILE, THE MINORITY CONCENTRATION,THE DIAMAGNETIC ENERGY CONTENT, AND THE NEUTRON OR GAMMA-RAYCOUNT RATES. IN ADDITION, THE ENERGETIC PARTICLES CREATED BY THE ION CYCLOTRON RF HEATING IN TOKAMAKS CAN BE EMPLOYED TO SIMULATE ENERGETIC ALPHA PARTICLES. BY SHIFTING THE LOCATION OF THE RESONANCE RELATIVE TO THE MAGNETIC AXIS, THERF POWER CAN BE DEPOSITED AT LOCALIZED MINOR RADII LOCATIONS. THIS SHIFT PERMITS STUDY OF ENERGETIC PARTICLE EFFECTS ON STABILITY BY ADJUSTING THE RELATIVE AMOUNT OF POWER ABSORBED BY THE TRAPPED AND PASSING PORTIONS OF THE DISTRIBUTION FUNCTION. MOREOVER, BECAUSE OF THE LARGE BANANA WIDTHS AND GYRORADII OF RF INDUCED ENERGETIC AND ALPHA PARTICLES, THESE EFFECTS ARE ALSO BEING INVESTIGATED IN PHASE I FOR ON-AXIS HEATING.