Fusion Plasma Heating with High Power Microwave and Millimeter Wave Tubes

Abstract

AbstractKey requirements for microwave power tubes for fusion heating are high efficiency, long life and stability in the presence of load mismatches. Operating frequencies presently range from UHF to 60 GHz, while future machines will operate at frequencies of 2 to 200 GHz with installed heating capacities of tens of megawatts. These requirements can be met with klystrons for frequencies from 1 to 20 GHz and with gyrotrons for 20 to 200 GHz.This paper presents details of existing klystrons and gyrotrons in plasma heating service. Design and performance information is presented for the VKS-8269A and VKC-7849 klystrons which provide 500 kW at 2.45 GHz and 250 kW at 4.6 GHz, respectively. Similar information is provided for the VGA-8050A and VGE-8060A gyrotrons which provide 200 kW at 28 and 60 GHz.The capabilities of klystrons and gyrotrons as a source of microwave power are reviewed. The design considerations controlling power capability and efficiency are described along with comments on reliability with...