Self-modulated generation observed in a delayed feedback relativistic microwave gyrotron

Abstract

Self-modulated generation regimes were studied in a delayed feedback relativistic gyrotron operating on the H01 mode with a central frequency of 9.2 GHz. At a fixed electron beam energy of 230 keV, an increase in the electron beam current from 10 to 45 A led to the transition from a stationary to periodic self-modulated generation regime. The modulation period was about 16 ns, while the relative amplitude of the modulation increased in proportion to the beam current, reaching up to 90%. The microwave pulse duration exceeded 6 μs at an average power of up to 1 MW. The experimental data obtained agree well with the results of simulation using the PIC code KARAT.