NONLINEAR SELF-AGREED THEORY OF FREE-ELEC TRON LASERS - EFFECT OF NONLINEAR GENERATION OF LONGITUDINAL ELECTRIC-FIELD

The phenomenon of the nonlinear generation of the electric field is sh own to take place at the parametric resonance interaction of the elect romagnetic waves in plasma of relativistic electron beam. Under certai n conditions this phenomenon may be a an independent mechanism of the saturation of the amplification of the signal wave in nonisochronous f ree-electron lasers. The effect of the given saturation mechanism as w ell as of the other mechanisms can be completely inhibited in the isoc hronous systems with an optimal supporting field and variation of pump wave length.