Abstract:
The possibility of using a two-dimensional (2D) distributed feedback to generate spatially coherent radiation by straight sheet and annular electron beams is studied. The schemes of sectional Cherenkov masers with the transverse synchronization of radiation performed in a 2D Bragg structure, which is arranged at the cathode end of the interaction space and conjugates the longitudinal and transverse (azimuthal) wave flows, is analyzed. By introducing dissipation into this structure, it is possible to increase the transverse dimensions of masers to a level on the order of 10$^3$ wavelengths with the corresponding increase in the total output radiation power without changing spectral characteristics and decreasing the energy conversion efficiency.