Start-up scenario in a 140 GHz gyrotron

Long-pulse, megawatt-class gyrotrons operate in very high-order modes. In order to excite only the desired mode in the presence of competing modes in such a gyrotron, the design should take into account the start-up scenario. In this paper the start-up scenario in the 140 GHz, 1 MW gyrotron developed at CPI is described. Simulations were done with the use of self-consistent non-stationary code MAGY.