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Possibilities for further optimizing the H¯/D¯ RF source
H. D. Falter, U. Fantz, P. Franzen, B. Heinemann, A. Encheva, M. Fröschle, D. Holtum, W.
Kraus, A. Lorenz, P. McNeely, R. Riedl, E. Speth, A. Tanga, D. Wünderlich
Max-Planck-Institut für Plasmaphysik, EURATOM Association, Postfach 1533, D-85740
Garching, Germany
Abstract: RF sources for the production of positive hydrogen ions have been successfully developed at
IPP for the AUG and the W7AS neutral beam heating systems [1], [2]. A collaboration on
high frequency ion source development for negative hydrogen ions between CEA Cadarache
and IPP Garching had been started in 1996 with first results reported in 1998 [2]. Compared
to arc sources RF sources have less parts, requiring just a source body, an RF coil, and a
matching transformer and are therefore cheaper to build and basically maintenance free in
operation. The simple design is potentially quite beneficial for ITER with its remote handling
requirements. In contrast to the arc sources RF sources do not require regular maintenance to
replace worn out filaments. Furthermore it is being speculated, that the arc current of the arc
sources might contribute to the plasma non-uniformity observed in the large arc sources [3].
Since September 2002 the development of the RF source is being supported by an EFDA
contract aimed at demonstrating that the ITER requirements can be met. The ITER targets for
current density, source pressure, and co-extracted electron fraction could already be achieved
or exceeded. Further improvements are mainly aiming at improved efficiency and reliability.
The present paper is to some extend of a speculative nature with the aim to provoke
discussions under the workshop participants.
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Synopsis (pdf)