High-energy bremsstrahlung on atoms in a laser field

P A Krachkov,A I Milstein,A Di Piazza

doi:10.1088/1742-6596/1508/1/012010

Abstract

The impact of a laser field on the process of photon radiation by an ultra-relativistic electron in an atomic field is investigated. The angular distribution and the spectrum of the radiated photon are derived. By means of the quasiclassical approximation, the obtained results are exact in the parameters of the laser field and the atomic field. It is shown that the impact of the laser field is significant even for fairly average values of the laser field parameters routinely achievable nowadays. Therefore, an experimental observation of the influence of the laser field on bremsstrahlung in the atomic field is a very feasible task.

Highlights

Quantum electrodynamics (QED) processes in atomic fields are of great interest from an experimental point of view, because the principles of detection of charged particles and photons at high energies are based on such processes
We have investigated in detail the impact of a laser field approximated as a plane wave on the process of photon radiation by an ultra-relativistic electron in an atomic field
By means of the quasiclassical approximation, the obtained results are exact in the parameters of the laser field and the atomic field

Summary

INTRODUCTION

Quantum electrodynamics (QED) processes in atomic fields are of great interest from an experimental point of view, because the principles of detection of charged particles and photons at high energies are based on such processes. The quasiclassical approach allows one to obtain results for an arbitrary atomic potential, taking into account the finite size of the nucleus and screening effects, and without requiring the analytical solution of the Dirac equation Another important example of processes in external fields are QED processes in strong laser fields. It was shown that the presence of the laser field induces a suppression of the cross section of e+e− pair photoproduction in an atomic field This effect is similar to the Landau-Pomeranchuk-Migdal effect (LPM) [14, 15], which is the suppression of e+e− photoproduction cross section and the bremsstrahlung spectrum at high energies due to multiple scattering by atoms in matter.

MATRIX ELEMENT

ANGULAR DISTRIBUTION AND SPECTRUM OF PHOTONS

MONOCHROMATIC CIRCULARLY-POLARIZED PLANE WAVE

WEAK LASER FIELD

CONCLUSION