The intensity-dependent frequency shift in Thomson scattering from a thermal plasma

The intensity-dependent frequency shift in Thomson scattering, having been a controversial effect in the literature and being as yet unobserved, is calculated within classical electrodynamics for the interaction of a strong linearly polarised plane wave laser pulse with a high temperature thermal plasma. For the highest reported intensities an approximate redshift of Δω/ωsub(i) = 10-2 is found. The simplifying assumptions involved in the derivation of the appropriate cross section are discussed. A few points relating to the possible detection of the frequency shift with available experimental facilities are touched upon. (author)