Nonlinear simulation of gyro-TWT amplifier with helical interaction waveguide

Two key techniques are presented to treat the initial-value problem of the partial mode and to monitor the calculation error in the nonlinear simulation of a gyro-TWT amplifier with helical interaction waveguide. Based on these techniques, a code is programmed and simulation results are in good agreement with the experimental data recorded by Denisov G G, et al. Influences of the electron-beam velocity spread, the period and depth of the helical corrugations on the efficiency are studied. The results show that the beam-wave efficiency is not sensitive to the velocity spread, but is dependent on the period and depth of the helical corrugations, and that the efficiency in the present experiment may achieve 25.6% by optimizing the helical corrugation parameters.