High Power and High Efficiency Operation of 170 GHz Gyrotron

The 170 GHz gyrotron for ITER demonstrated the stable and steady state 1000s operation with the output power of 0.6 MW and the efficiency of 45% by depressed collector. The remarkable progress was obtained with optimization of a built-in launcher and mirrors for significant reduction of the stray radiation to ~2% of the output power, improvement of electron beam quality for high oscillation efficiency and control of constant beam current for stable oscillation. The result indicates a promising prospect for development of a 1 MW-CW-50%, 170 GHz ITER gyrotron.