Generation of a periodic train of ultrashort electromagnetic pulses based on the passive mode-locking effect in a scheme with two coaxial relativistic electron beams

The theoretical analysis of the generation of a periodic train of ultrashort microwave pulses based on the passive mode-locking effect in a scheme with two parallel coaxial electron beams formed by a single cathode and transported in the same vacuum volume was carried out. The external cylindrical beam in rectilinear motion along the periodic decelerating system amplifies a signal, while the internal paraxial beam provides nonlinear cyclotron absorption. Simulations show that on the basis of the microsecond accelerator SATURN (IAP RAS) with particle energy of 210 keV, currents of amplifying and absorbing beams of 60 A and 23 A, respectively, it is possible to generate subnanosecond (~ 300 ps) pulses with a central frequency of 37.5 GHz, a peak power up to 10 MW and a repetition period of ~ 1.6 ns.