Statistical properties of photon emission from relativistic electrons in intense electromagnetic fields

Ultrahigh-intensity laser-matter interactions generate high-energy photons, which carry essential information about the dynamics in the interaction region. Several models are developed to describe the statistical properties of emitted photons and the total photon yield produced by an electron beam propagating through a static, homogeneous magnetic field. The accuracy of these models, as well as the Fokker-Planck approximation, is verified using first-principles Monte Carlo simulations. While these models are valid in the quasiclassical regime, it is demonstrated that a model can be constructed to describe photon statistics in both the quasiclassical and quantum regimes. The extension of the developed approach to the strong quantum regime is discussed. Finally, the results are generalized to the case of an electron beam interacting with an ultrashort, high-intensity laser pulse.