Bochum 2002 – scientific programme

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P: Plasmaphysik

P 17: Plasmadiagnostik

P 17.4: Talk

Wednesday, March 20, 2002, 17:25–17:40, HZO 60

Investigations on the Effect of Argon on the Production of H⁻ Ion Beams for the Heating of Fusion Plasmas — •McNeely Paul, Kraus W., Franzen P., Speth E., Bandyopadhyay M., Hu C., Heinemann B., and Riedl R. — Max-Planck-Institut für Plasmaphysik, Technologie, Boltzmannstrasse 2, 85748 Garching

One of the primary heating mechanisms for the proposed International Thermonuclear Experimental Reactor (ITER) Project will be Negative Ion Based Neutral Beam Injection (NI-NBI). Producing an intense, high energy, negative ion beam is technically challenging and over the past five years at IPP work has been undertaken to develop a RF based negative hydrogen ion source.

An interesting feature of the RF driven NI source is the fact that the H ⁻ intensity can be increased by the addition of argon. This paper will focus on the addition of argon to the gas mix of the source to enhance the extracted H⁻ current. Presented will be the results of studies on the effect of argon on: plasma parameters, beam extraction characteristics, and other studies carried out. In general, argon addition in the range of 10-30% enhances the extracted H ⁻ current by a factor of at least 2 but produces only a small change in the plasma parameters. At the present time no explanation for the enhancement due to argon addition exits in the community but the paper will present some of our current hypotheses on the matter. Plans for future studies will also be presented.