Development of 100 GHz band gyrotron and its application for JT-60U and ITER

A status of high power gyrotron development at JAERI is presented. Gyrotrons of 170 GHz and 110 GHz are under development for ITER (International Thermonuclear Experimental Reactor) and JT-60U, respectively. Both gyrotrons have a low loss synthetic diamond window that enables Gaussian beam output over 1 MW and a depressed collector. The output power of -1 MW/3 s was obtained for the 110 GHz gyrotron. A heating experiment was carried out using three 110 GHz gyrotrons on the JT-60U, and an effective local heating capability in plasma was demonstrated (e.g., attainment of 15 keV of electron temperature). As for 170 GHz device, an output power of 1.2 MW with electron beam of 85 kV/49 A was obtained for a short pulse (/spl sim/5 ms). The efficiency of /spl sim/52% was obtained at 1.0 MW with a depressed collector operation of 36.5 kV.