Space-charge and cyclotron waves in a Raman free-electron laser

Effects of the wiggler field on the propagation of two types of space-charg e waves in a Raman free-electron laser are studied. The relativistic electr on beam is affected by an axial magnetic field and only partially fills a c ylindrical metallic waveguide. Using the electrostatic approximation in the beam frame and an appropriate boundary condition a set of two equations ar e found as the dispersion relation. These equations are solved numerically to study the characteristics of the plasma-like and the cyclotron-like wave s.