Thermal regimes of relativistic magnetron oscillators

Experiments with relativistic magnetron oscillators (RMOs) using high-current electron accelerators allowed a level of output power from several hundred megawatts to several gigawatts to be reached at an efficiency of 10–30%. The operation principle of RMOs is identical to that of classical devices, but the determination of working regimes and calculation of output characteristics require taking into account relativistic corrections. In addition, a high cathode-anode voltage and high current in RMOs lead to some specific effects related to the damage of anode units as a result of thermal shocks. RMO operation in a periodic pulsed (pulse train) regime, which is of the most practical interest, imposes stringent requirements on the working life of anode units. The principles of choice of the material and design for the anode units of RMOs are formulated. Calculations of the limiting thermal regimes of RMO operation depending on the electron beam power flux density and the off/duty ratio of heating pulses are presented. Methods of increasing the working life of anode units are proposed.