Progress of the development of gyrotron and gyrotron system for ITER

A high power gyrotron and a power supply system have been developed for ITER. Recently, two gyrotrons are fabricated. One is a 170 GHz-TE
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high order mode gyrotron. The other is a 170 GHz-TE
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and 137 GHz-TE
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dual-frequency gyrotron. The 170 GHz-TE
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gyrotron is loaned in KSTAR tokamak and 600 kW/10 s RF was injected into the plasma. The dual-frequency gyrotron was achieved 760 kW/46 %/20 s for 170 GHz and 540 kW/42 %/20 s for 137 GHz. Both gyrotrons successfully generate 1 MW power in a short pulse. The development of a power supply and auxiliary systems are also underway. A 5kHz 100% beam on/off modulation is achieved by using an anode-cathode short-circuited switch. A high speed frequency change with a super conducting magnet that has an insert coil inside the bore is demonstrated.