Lower Hybrid Wave Injection Experiments on MST
Abstract
Current drive using RF waves has been proposed as a means to reduce the tearing fluctuations responsible for anomalous energy transport in the RFP. A traveling wave antenna that operates at 800 MHz and n_\|≈7.5 is being used to launch lower hybrid waves into MST to assess the feasibility of this approach. Power handling capability has been increased from 50 kW to 75 kW in both launch directions. Phase measurements inside the antenna allow measurement of n_\|, which remains constant under varying plasma conditions as desired for wave accessibility. Hard x-rays (HXR) have been observed during lower hybrid injection. Movable HXR detectors are used to determine the location of HXR emission. Improved Fokker-Planck modeling of the expected emission is being performed to compare with experiment. A boron-nitride limiter covering the antenna aperture has recently been removed, and plasma parameter scans will be done to measure its effect on antenna performance and HXR emission.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2004
- Bibcode:
- 2004APS..DPPNP1042K