Optimization of RF field profiles for enhanced gyrotron efficiency

Physically realizable RF field profiles are investigated with the objective of maximizing gyrotron efficiency. For this purpose, a study is made of the resonant properties of continuous profile open resonators and truncated cones cavities, the former allowing greater flexibility in the shaping of asymmetric axial field profiles. High perpendicular efficiencies (η ⊥ ⋍ 0.86) have been calculated for both type of cavity, for interaction at the fundamental cyclotron harmonic and for uniform external magnetic fields. A maximum-efficiency scaling parameter has been introduced that is applicable to a variety of field profiles.