First Experiments On Icrf Discharge Generation By A W7-X-Like Antenna In The Uragan-2m Stellarator

In support of the ICRF experiments planned on the Wendelstein 7-X (W7-X) stellarator, i.e. fast ion generation, wall conditioning, target plasma production and heating, a first experimental study on plasma production has been made in the Uragan-2M (U-2M) stellarator using W7-X-like two-strap antenna. In all the experiments, antenna monopole phasing was used. The W7-X-like antenna operation with launched radiofrequency power of similar to 100 kW have been performed in helium (p = (4-14) x 10(-2) Pa) with the vacuum vessel walls pre-loaded with hydrogen. Production of plasma with a density higher than 10(12) cm(-3) was observed near the first harmonic of the hydrogen cyclotron frequency. Operation at first hydrogen harmonic is feasible in W7-X future ICRF experiments.