Studies on a 120 GHz, 1.0 MW, longpulse gyrotron for plasma start-up in ITER

Abstract

In this work, the initial design concept of a 1.0-1.5 MW, longpulse gyrotron operating at 120 GHz, for plasma start-up in the ITER has been presented. Mode competition and mode selection procedures are carried out for various candidate modes and the modes TE24,8 or TE24,7 are chosen as probable operating modes. Cold cavity design and self-consistent and time dependent calculations are carried out for the TE24,8 mode and power and efficiencies are computed. The nominal beam parameters are chosen to give a moderate to low velocity spread. The initial results are indicating that an output power of well over 1.0 MW, CW can be achieved at 120 GHz with the TE24,8 mode as the operating cavity mode. Further investigations to consolidate the design concept are in progress at the time of reporting this paper.