Amplification and frequency-locking in a TWT using cyclotron depression of positive feedback

In the present work we suggest to use cyclotron absorption to suppress a wave that is responsible for feedback in traveling wave tubes (TWTs) without removing reflections and other causes of parasitic self-excitation that can lead to controlled gain by varying the magnitude of the guide magnetic field inside the stationary region of cyclotron absorption (RCA). We illustrate amplification in the RCA using a self-consistent theory of stationary operation of a TWT accounting for the cyclotron resonance of electrons with the wave that is responsible for positive feedback, and interaction of electrons with the forward wave accounting for the condition of Cherenkov synchronism.