Prospects for high-power quasi-optical gyrotrons operating in the millimeter-wave range

The prospects for high-power (several megawatts) quasi-optical gyrotrons operating in the high-frequency region (>or=150 GHz) are considered. The analysis is mainly concerned with the physics of interaction between the annular electron beam and the electromagnetic field within the quasi-optical resonator, together with the constraints required by long-pulse or CW operations. It is shown that powers of several megawatts at frequencies exceeding 150 GHz are possible if one can maintain single-mode operation in the overmoded quasi-optical resonators. A thorough performance study of the magnetron injection gun for such high-power gyrotrons is carried out using the adiabatic theory as well as numerical simulations.>