Planar W-band Cherenkov maser with two-dimensional periodic slow-wave structure based on the «ELMI» accelerator: design parameters and first experiments

The project of a powerful spatially-extended W-band Cherenkov maser of planar geometry is currently being developed in collaboration between the BINP RAS and IAP RAS. The experimental basis of the project is the «ELMI» accelerator complex forming the electron beams with parameters of 1 MeV / 3 - 5 kA / 3 μs and a cross-section of 0.4 cm × 17 cm (sheet configuration). A key component of the electrodynamic system of the generator is a slow-wave structure with two-dimensional periodic corrugation, which provides a two-dimensional distributed feedback mechanism. The paper presents the simulation results of the developed generator and data from the first series of experiments on its realization, in which the excitation of the orotron-type modes was observed. Approaches to the suppression of the parasitic modes and the implementation of the surface wave generation regime with the prospect of the generated radiation power enhancement are discussed.