Wiggler-field effects on the space-charge waves of a Raman free-electron laser

An analysis of the propagation of a space-charge wave through the wiggler a nd axial magnetic fields of a free-electron laser is presented. The relativ istic electron beam is contained within and only partially fills a cylindri cal metallic waveguide. A theory is developed using lab-frame Maxwell and f luid equations in a form which is equivalent to the electrostatic approxima tion in the beam frame. The computational method of determining the dispers ion relation is described and some numerical results are presented which il lustrate effects arising from the wiggler and the partially filled waveguid e. [S1063-651X(99)02208-4].