THEORY OF THE FREE-ELECTRON LASER-BASED UPON A COAXIAL HYBRID WIGGLER

A 3D nonlinear FEL formulation based upon a Coaxial Hybrid Iron (CHI) wiggler is described. The CHI wiggler is created by insertion of a cen tral rod and an outer ring (composed of alternating ferrite and nonfer rite spacers) along the axis of a solenoidal. Relatively high field st rengths can be achieved with the CHI wiggler at shorter wiggler period s than is possible in many other conventional wiggler designs. The for mulation is a slow-time-scale analysis of the interaction of an annula r electron beam with the CHI wiggler in a coaxial waveguide, Simulatio ns are presented for W-band operation. The results indicate that opera tion over a wide bandwidth is practical, and that the uniform- and tap ered-wiggler bandwidths are comparable.