DEPOSITION OF NEUTRAL BEAM IMPURITIES IN THE STELLARATOR W7-A AND W7-AS
Experimental and theoretical work has shown that light impurities are deposited deeply into the plasma of the Stellarator W7A, where the neutral beams are injected nearly perpendicularly into the plasma. Computations using the Monte-Carlo Code ODIN have shown that the absorption of fast oxygen atoms in the W7A plasma is higher than the absorption of fast hydrogen atoms and that up to 80% of the injected oxygen atoms can be trapped inside a radius of 5 cm. Tangential neutral injection is planned for the stellarator W7AS, the successor of W7A. The particle deposition profiles for hydrogen and oxygen and also for high-Z impurities (Ti, Mo) have been computed for this new experiment in order to compare the impurity deposition with the W7A case. The results show that the beam impurities will not be deposited in the center region of the plasma if the W7AS plasma density there exceeds 10**14 cm**-3.
Bibliographic Reference: 4TH INTERNATIONAL SYMPOSIUM ON HEATING IN TOROIDAL PLASMAS, ROMA (ITALY), MARCH 21-28, 1984 VOL. I. BOOK, AVAILABILITY: EEUR WRITE TO MONOTYPIA FRANCHI, ST. LUCIA + VIALE UMBRIA NO. 28, 06012 CITTA DI CASTELLO, PERUGIA (ITALY), USD 65 (BOTH VOLUMES)
Record Number: 1989124024000 / Last updated on: 1987-01-01
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