The cubic nonlinear theory of plasma-beam superheterodyne free electron laser of dopplertron type

The multiharmonical cubic nonlinear theory of plasma-beam superheterodyne free electron laser of dopplertron type is constructed. The unusual retarded electromagnetic wave is used as a pumping wave. Multi-harmonious interaction of waves is taken into consideration. Analysis of the levels and mechanisms of saturation is carried out. It is found that prospects of practical use of the considered systems for generation of especially powerful electromagnetic signals of the mm-range could be rather promising.