Net inverse-bremsstrahlung (NIB) acceleration of a high-energy electron beam in an axial electrostatic wave

Abstract

It is shown that stimulated emission is an intrinsically incoherent-phase phenomenon arising from the uncertainty principle, and that therefore the laser gain cannot be described by any classical model, which must be coherent in all aspects. The force due to the net inverse-bremsstrahlung (‘NIB force’) acting on a high-energy electron beam travelling in an undulating field whose wave vector is collinear with the electron beam (‘collinear wiggler’) is found by extending the quantum kinetic theory of the free-electron laser. In the case that an axial electrostatic wave is used as the catalysing field for the net multi- photon inverse bremsstrahlung, it is shown that NIB acceleration is practical only when the potential amplitude (in terms of the electron energy) of the laser wave, [eA0], is comparable to or larger than the electron rest energy mc2.