Research on a Long-Pulse High-Power 170GHz Gyrotron

The MW gyrotrons are key devices in ECRH of magnetic confinement nuclear fusion systems. In order to achieve the high-power and long-pulse of the gyrotron, which will be adopted in the CFETR, a $\mathbf{TE}_{\mathbf{25}.\mathbf{10}}-\mathbf{mode}$ 170GHz gyrotron research are given in this paper. A single-anode magnetron injection gun (MIG) and the cylindrical resonant cavity operating at the $\mathbf{TE}_{\mathbf{25}.\mathbf{10}}-\mathbf{mode}$ are designed and optimized by PIC. The theoretical output power of the gyrotron with operating Voltage 75 kV, electron current 45 A is about 1.1 MW, corresponding to electron efficiency of 32.6%. The prototype of the gyrotron with the mode convertor and single-depressed collector has been fabricated and tested preliminarily. The experimental results of the 170 GHz gyrotron are that an output power of ~520 kW with Gaussian beam has been achieved at 200-ms pulse length in operating voltage 53.3 kV, electron beam 32 A.