Electrons trajectories in electromagnetically pumped free electron laser with a constant reverse guide magnetic field

An exact solution to the quartic equation in the wiggler frequency ωw , which represents the dispersion relation for this system, is obtained. The effects of the frequency of the wiggler ωw on the electron’s velocities (v|| and vw) are investigated. The regions of interest for the allowed wiggler frequency ωw for both group I and group II electron trajectories are discussed.