INDUCED SCATTERING OF PLASMA-WAVES BY A RELATIVISTIC ELECTRON-BEAM

The general case of induced coherent scattering of plasma waves by a r elativistic electron beam is considered for noncollinear wave vectors of interacting waves, specifically, the plasma pump wave, the scattere d electromagnetic wave, and the high-frequency space-charge wave produ ced by the combined action of incident and scattered waves. In terms o f the three-wave interaction model, the general nonlinear dispersion r elation describing the initial stage of the induced scattering is obta ined. Both the Raman and Compton mechanisms of scattering are consider ed. The corresponding amplification factors and the dependence of thes e factors on the angular characteristics are obtained. The frequencies of the scattered electromagnetic waves are determined. The possibilit y of using plasma waves as effective undulators is discussed in relati on to the free-electron laser realization for obtaining short wave rad iation by using moderately relativistic electron beams.