Theoretical and design aspects of a grooved waveguide for compact FEL

Abstract

This paper is dedicated to the study of novel waveguide resonators for compact FELs. The necessity of using low loss structures together with the requirement of confining the radiation in the plane perpendicular to the magnetic field led us to the design of waveguides with a well-shaped groove along the longitudinal direction of wave propagation. Together with the general theory, the triangular and the rectangular groove cross-sections are analysed in the framework of the ENEA Far InfraRed Compact FEL project.