Thorough Simulation of High-Power Gyrotron Cavity Interaction in the Hard Excitation Regime

Using the new interaction code Phaedra, a thorough and systematic investigation of the operation of a high-power gyrotron cavity in the hard excitation regime took place. The preliminary result of this analysis shows that in the hard excitation regime, the nominal mode can potentially be excited at more than one frequency with a difference in the range of few tens of MHz and with a significant power difference at the same accelerating voltage. Furthermore, improper choice of parameters for the startup simulations can guide to an important overestimation of the stability of the mode at higher voltages.