Photon Landau damping of electron plasma waves with photon recoil

Photon Landau damping of electron plasma waves with relativistic phase velocity is described, using a photon kinetic theory where photon recoil is taken into account. An exact form of the wave kinetic equation is used. Kinetic and fluid regimes of photon beam instabilities are discussed. Diffusion in the photon momentum space is derived and a quasilinear wave kinetic equation is established. In the present approach, photon recoil effects associated with the emission or absorption of plasmons are included. The neglect of recoil, which is equivalent to using the geometric optics approximation, reduces the present results to those already existing in the literature