Photon acceleration: three-wave interaction

Summary form only given. The possibility of photon acceleration in a plasma was studied from the viewpoint of three-wave interaction. A photon with momentum hŁq_phi and energy hŁω_phi combines with a plasmon with momentum hŁq_pl and energy h Łω_pl to give a photon with momentum h Łq_phf and energy hŁω_phf. It was observed that the interaction vertex function for the plasmon-particle can be obtained by the use of the interaction Hamiltonian between particles and longitudinal quasiparticles. Calculation of the vertex function for a specified three-wave interaction process reveals that no transition occurs if the plasma is cold and stationary. It is found that the transition probability reaches a maximum when the plasma particles move in the direction of longitudinal plasma oscillations (plasmons) along with the direction of polarization of vector potential A, resulting in the upshifting of the frequency of the outgoing photon fields