HIGH-GAIN STRONG PUMP FREE-ELECTRON LASERS WITH FAST 2-PI KW SPATIAL OSCILLATIONS/

In the high gain strong pump regime, the radiation field amplitude and phase can vary substantially over a wiggler period. Also, due to the periodic transverse motion, the longitudinal electron energy suffers l arge variations over the same distance. Because of these consideration s, the spatial average that leads to the classical one-dimensional fre e-electron laser equations is not applicable here. Thus the rederived equations suitable for the high gain strong pump regime contain 2pi/k( w) periodic terms. Comparisons with the Electron Laser Facility (ELF) experiments of the Lawrence Livermore National Laboratory [Phys. Rev. Lett. 54, 889 (1985); 57, 2172 (1986); Phys. Rev. A 35, 2184 (1987)] o n the operational characteristics including the relative phase of the radiation field are made.