CO- AND COUNTERINJECTION HEATING IN THE W7-A STELLARATOR
Neutral injection heating in the W7A stellarator has been much more effective than originally expected. The reasons for this have been described several times in the past The magnetic field configuration of W7A has been reversed now, thus changing the injection from "co" to "counter". In the experiment, the heating was observed to be as strong as for co-injection. In particular, the current free plasma could be established as well, whereas a theory neglecting the electric field would predict an efficiency about a factor of 2 lower. Radial electric fields, however, improve the confinement of the fast particles and therefore increase the computed heating efficiency for both co- and counter-injections. Within the approximation of a parabolic potential profile, a potential drop of > 3 kV across the plasma is necessary to explain the observed similarity of co- and counter-injections. This again confirms the reduction of orbit losses by self-generated electric fields.
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), US USD 65 (BOTH VOLUMES)
Record Number: 1989124022200 / Last updated on: 1987-01-01
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