Preliminary Electron-Cyclotron-Heating Results on Doublet III Using an Outside Launch

摘要

Electron-cyclotron-heating experiments have been carried out on the Doublet III tokamak. Two 60-GHz gyrotrons were used to generate about 255 kW of power delivered to the plasma in the ordinary-mode polarization. The antenna launches a 16 exp 0 FWHM beam from the large major radius side (outside) of the plasma at a beam center angle of 12 exp 0 from a major radius. Pulses up to 85 msec long were applied, with the fundamental resonance (21.4 kG) near the plasma center. Plasma current was 300 to 350 kA, and the configuration was mostly expanded boundary with an elongation of 1.4 to 1.6 and density of 2 to 3 x 10 exp 13 cm exp -3 . Electron-temperature increases up to 1 keV at the plasma center due to ECH are found by Thomson scattering and electron-cyclotron radiation at the second harmonic. Soft x-ray analysis also shows central electron heating and profile broadening when the resonance is moved outside of the plasma center. (ERA citation 08:030901)