A Slow Wave Free-Electron Laser

IEEE Trans. Plasma Sci. 17, 583 (1989)https://ireap.umd.edu/10.1109/27.311961989Journal ArticlePlasma, Accelerator, and Nuclear Physics

A simple calculation of a free-electron laser in the Compton regime that uses a dielectric-lined waveguide is presented. The introduction of a dielectric lining in a free-electron laser considerably reduces the requirements on beam voltage for generating a given frequency omega₁ = k₀c/(1 - v_beta/c), where k₀ is the wiggler wave period eta is the effective index of refraction (1< eta < square root epsilon ) and epsilon is the permittivity. The system supports electromagnetic waves whose Poynting flux is largely concentrated in the dielectric; hence the electron beam is required to propagate close to the dielectric lining. The mode structure and dispersion behavior of the guiding system without the beam are discussed. a thin annular beam is introduced, and a perturbation theory is used to obtain the frequency and growth rate of radiation.