A high harmonic, low field gyrotron: Comparison between the cyclotron maser and peniotron-like interactions

The highly efficient mth harmonic electron cyclotron maser interaction for a TE
m11
gyrotron oscillator is compared with the (m-1)th harmonic peniotron-like interaction. Identical cavities and electron beams are used. Start oscillation conditions from weak field linear theory are given, as well as optimized non-linear efficiencies. The peniotron-like interaction leads to optimized efficiencies of ≲ 65%, while those for the electron cyclotron maser interaction are limited to ≲ 25% in the cases studied.