HIGH-POWER MULTI-ELECTRON-BEAM CHERENKOV FREE-ELECTRON LASERS AT MM WAVELENGTHS

A multi-electron-beam Cherenkov free-electron laser can use a multi-di electric waveguide to generate high-power coherent radiation at mm wav elength. Presented is a mode analysis of the device, allowing a detail ed description of the dispersion relations and field distributions of the waveguide for the important modes and the start current for each m ode. The microwave loss of the waveguide and the mode competition prob lem are also discussed. The device is shown capable of producing radia tion at millimeter wavelengths with power an order higher than that us es a dielectric-lined circular waveguide.