Mode competition in harmonic magnicon amplifiers

Summary form only given. A time-dependent, multimode gyrotron code has been modified to examine competition in the output cavity between the phase-synchronous operating mode and other nonsynchronous modes which interact via the conventional gyrotron interaction. Calculations have been carried out for magnicons with TM/sub 410/ and TE/sub 411/ mode output cavities and include the effect of a spread in gyro-angles in the scanning electron beam. Our results indicate that the TM/sub 410/ mode is subject to strong competition from the TM/sub 110/ mode interacting at the fundamental cyclotron harmonic, while the TE/sub 411/ mode experiences weaker competition from the TE/sub 121/ mode interacting at the second cyclotron harmonic.