Semiclassical theory of laser-assisted radiative recombination

Authors

Ilya I. Fabrikant, University of Nebraska-LincolnFollow
H. B. Ambalampitiya, University of Nebraska–Lincoln

Date of this Version

5-4-2020

Citation

I. I. FABRIKANT AND H. B. AMBALAMPITIYA. PHYSICAL REVIEW A 101, 053401 (2020). DOI: 10.1103/PhysRevA.101.053401

Comments

Used by permission.

Abstract

We study the process of laser-assisted radiative recombination of an electron with a proton by using a semiclassical approach involving calculation of classical trajectories in combined laser and Coulomb fields. Due to chaotic scattering in the combined fields, the radiation probability as a function of the impact parameter and the constant phase of the laser field exhibits chaotic behavior and fractal structures. We obtain a strong enhancement of the recombination cross section as compared to the laser-free case due to the Coulomb focusing effect. For sufficiently low incident electron velocities the cross section becomes infinite, and we limit it by assuming a finite laser pulse duration. With the pulse duration t_p = 5 ps we obtain the gain factor for capture into the ground state of the hydrogen atom of about 220 for infrared fields in the intensity range 10⁹–10¹² W/cm². The gain factor grows with t_p but slower than linearly.