Projects of Sub-GW Power Sub-THz Band Planar Cherenkov Masers with Two-dimensional Distributed Feedback

The possibility of advancing relativistic spatially-extended Cherenkov masers of planar geometry driven by intense sheet electron beams into the sub-THz frequency range is studied. It is shown that the use of 2D-periodic slow-wave structures providing the mechanism of two-dimensional distributed feedback makes it possible to ensure high coherence of radiation of a sub-GW power level in generators of this type with transverse sizes amounting to hundreds of wavelengths. The design parameters for the implementation of such super-power Cherenkov generators based on the "ELMI" accelerator complex, which are being developed in collaboration between the BINP RAS (Novosibirsk) and the IAP RAS (Nizhny Novgorod), are discussed.