Electron beam acceleration by nonresonantly driven relativistic electron plasma waves

Acceleration and heating of a relativistic electron beam induced by nonlinear Landau damping of intense electromagnetic waves in a plasma are investigated theoretically based on kinetic wave equations and momentum-space diffusion equations derived from relativistic Vlasov--Maxwell equations. Two electromagnetic waves excite nonresonantly a beat-wave driven relativistic electron plasma wave with a phase velocity near the speed of light [vp=c(1-γ-2p)1/2, γp=ω/ωpe]. This wave interacts nonlinearly with the electron beam and accelerates effectively it to a highly relativistic energy γpmec2. When the beat-wave frequency equals the electron plasma frequency, the beam acceleration and the beat-wave energy density become maximum, and they are equal to those by stimulated Raman scattering