RESONANT COUPLING OF ION-CYCLOTRON WAVES TO ENERGETIC HELIUM-IONS

First measurements were performed to test a model prediction which sta tes that the off-axis coupling of ion-cyclotron waves to energetic hel ium ions can generate either an inward or an outward drift of these pa rticles. Ion-cyclotron waves with a power or up to 1 MW are coupled to energetic particles at the high field side, the low field side, or in the center by varying the toroidal magnetic field. When changing the heating power or the resonance location, the variation of the concentr ation of the energetic helium in the plasma agrees qualitatively with the model predictions.