2.5: Design of major components for a 4 MW 170 GHz coaxial-cavity gyrotron

For future nuclear fusion reactors it is desirable to increase the RF power per gyrotron tube used for electron cyclotron resonance heating. Using gyrotrons with higher output power will reduce their overall number and the number of super-conducting magnets required. In this work the feasibility of a 4 MW 170 GHz continuous wave (CW) coaxial-cavity gyrotron is investigated. Starting from a mode selection procedure proper studies of all major gyrotron components have been performed. Designs for the coaxial cavity, the electron gun, the two-beam quasi-optical output coupler and the collector are presented. All layouts are optimized to guarantee high efficiency and consider long-pulse operation effects.