EXPERIMENTS WITH ELECTRON BERNSTEIN WAVES AT THE WEGA STELLARATOR

This paper reports about electron Bernstein wave (EBW) heating and current drive experiments at 2.45 GHz and experimental set-up for 28 GHz at the WEGA Stellarator. The device allows continuous plasma operation for a magnetic field of up to 0.5 T. For the 2.45 GHz the OXB mode conversion could be investigated in detail by HF-probes. The results were consistent with full wave simulations. The propagation of EBWs was calculated by a 3D- ray-tracing code for both 2.45 GHz and 28 GHz. The results were confirmed by the measurement of the local resonant power deposition with the power modulation technique. The predicted EBW driven toroidal current for the 2.45 GHz could be clearly detected experimentally by total and local measurement. For the 28 GHz a waveguide and antenna system, which is optimized for OXB-conversion, was build-up.