Frequency multiplication in a high-current relativistic gyrotron for obtaining high-power THz-band radiation

Using averaged equations and 3D particle-in-cell simulations, we investigate the frequency multiplication regime in a high-current relativistic gyrotron operating in 0.1 THz frequency band. We demonstrate that the ratio of the 3rd harmonic power and the fundamental cyclotron resonance power can reach 0.4–0.8%, which aloows for obtaining the 0.3 THz radiation with sub-MW output power level.