Multimode interaction and multiwave radiation of Cerenkov generators with overmoded slow-wave structures

A nonlinear time-domain hybrid code for Cerenkov generators with overmoded slow-wave structures has been developed in which the analytical representation of an axially symmetric electromagnetic field and particle-in-cell method for an electron beam was used. To present a summary electromagnetic field of the open resonator, the supplementary functions are used along with the high-Q functions corresponding to longitudinal modes. The code was used for numerical simulation of different regimes of the beam and field interaction near the pi -type oscillations of TM(01)mode in a one-sectional slow-wave structure. In the output radiation the main contribution is made by the modes TM01 and TM02. Calculation results are compared with the experimental data in the wavelength and generation efficiency.