3D beam-wave interaction study in a dielectric loaded W-band gyro-TWT using MAGIC

Abstract

In this paper, Particle-in-Cell (PIC) simulation study of a lossy dielectric loaded gyrotron travelling wave tube (gyro-TWT) amplifier operating in W-band is presented. The RF interaction region is loaded uniformly with a lossy dielectric to attenuate the potential backward wave oscillations (BWO's) caused by competing modes including the fundamental harmonic TE11, TE21, and second harmonic TE02 modes. The complete RF interaction circuit of gyro-TWT is simulated using 3D PIC code "MAGIC" to study its beam-wave interaction behaviour. The simulation predicted a peak RF power of ~190kW in a fundamental TE01 mode with a conversion efficiency of ~30% and a high gain of ~63dB for a non-spread gyrating 70kV, 9A electron beam. © 2018 IEEE.