Generation of Train of Ultrashort Ka-band Pulses by Helical Gyro-TWTs with Nonlinear Cyclotron Resonance Absorber in the Feedback Loop

Based on a time-domain model we demonstrate that a periodic train of powerful ultrashort microwave pulses can be generated in an electron oscillator consisting of helically corrugated gyrotron travelling wave tube (gyro-Twt)and saturable absorber based on cyclotron resonance interaction of radiation with initially rectilinear electron beam. The gyro-TWT operates at the second cyclotron harmonic while in the absorber interaction at the fundamental harmonic should be realized. According to simulations with the parameters of an experimentally realized Ka-band gyro-TWT, the peak power of generated pulses with duration of 200 ps is about 400 kW.