A. Isayama, Y. Ikeda, S. Ide
Feb 21, 2002
Journal name not available for this finding
ECRF experiments in JT-60U have been started since 1999. ECRF system in JT-60U is characterized by a) collector potential depression (CPD) gyrotrons, b) two diamond windows at the gyrotron output and the vacuum vessel, c) a steerable mirror which enables to change a poloidal injection angle, d) two grooved polarizing mirrors which enable to change elliptical polarization of the incident wave, e) sixty-meter evacuated transmission line with corrugated waveguides. Duration and output power of the gyrotrons have been steadily increased, and ECRF of ∼1.5 MW was successfully injected to the torus for 3 seconds with 3 gyrotrons. By using the ECRF system, the following experimental results are obtained: a) An m/n=3/2 neoclassical tearing mode was completely stabilized by the fundamental ECH/ECCD. The optimum injection angle for the mode suppression was identified by scanning the injection angle during a discharge. Real-time detection of a neoclassical tearing mode and ECRF injection were also performed; b) EC-dr...