Demonstration of a high-power long-pulse 140-GHz gyrotron oscillator

CPI Microwave Power Products Div., Palo Alto, CA, USA
IEEE Transactions on Plasma Science (Impact Factor: 0.95). 07/2004; 32(3):867 - 876. DOI: 10.1109/TPS.2004.828815
Source: IEEE Xplore

ABSTRACT A high-power long-pulse 140-GHz gyrotron oscillator has been designed, constructed, and tested. Key features of the gyrotron include an internal converter to transform the TE28,7,1 operating mode to a Gaussian output beam, a single-stage-depressed collector, and a chemical-vapor-deposition diamond output window. Peak output powers up to 930 kW at 34% efficiency have been demonstrated at 5-ms pulse lengths. Due to power supply limitations, long-pulse operation was not possible for beam currents above 25 A. At 25-A beam current and 500-kW output power, pulse lengths up to 700 s in duration were achieved. The gyrotron has been shipped to the Wendelstein 7-X facility in Greifswald, Germany, where long-pulse demonstrations up to 180s will be carried out at the 930-kW power level.