Progress in developments of high-power, long-pulse and multi-frequency ECH/CD system for JT-60SA

A gyrotron and a waveguide transmission line, which were developed for electron cyclotron heating and current drive in JT-60SA, have been tested to evaluated its high-power, long-pulse and multi-frequency capabilities. High-power oscillations up to 1.8 MW at 110 GHz and 1.3 MW at 138 GHz have been obtained so far. The spatial distribution of the temperature increase of the waveguide transmission line with 7 miter-bends has been measured and effective cooling method was developed.