Improved phase and gain stability in gyro-traveling wave amplifiers with detuned cyclotron mismatch

Summary form only given. An ultrahigh-gain gyro-traveling wave amplifier developed at National Tsing Hua University has recently been modeled using the time-dependent, self-consistent Maryland gyrotron code (MAGY). We compare the sensitivity of gyro-TWT phase to variations in electron accelerating potential and guiding magnetic field for the case of optimum gain and efficiency, and for detuned cyclotron mismatch. The results show that gyro-TWT gain and phase are more sensitive to fluctuations in operating parameters in the optimized case than when detuning is applied. A mapping of gain and phase stability vs. operating parameters will be presented and compared with experiment results. An example is given showing that reducing the gain 2 dB (from 70 dB to 68 dB) in the ultrahighgain gyro-TWT improves phase stability due to beam voltage variation from 35 deg/kV to 15 deg/kV. Also shown is how phase and gain stability relate to improved signal integrity in coherent systems.