Modelling radiation emission in the transition from the classical to the quantum regime

Abstract

An emissivity formula is derived using the generalised Fermi–Weiza?cker–Williams method of virtual photons, which accounts for the recoil the charged particle experiences as it emits radiation. It is found that through this derivation the result obtained by Sokolov et al using QED perturbation theory is recovered. The corrected emissivity formula is applied to nonlinear Thomson scattering scenarios in the transition from the classical to the quantum regime for small values of the nonlinear quantum parameter ?. In addition, signatures of the quantum corrections are identi ed and explored.