Electron-impact ionization of atomic hydrogen in the presence of a laser field

The influence of a laser field on the dynamics of fast (e,2e) collisions in atomic hydrogen is analyzed in the asymmetric, coplanar geometry. Particular attention is devoted to the construction of the dressed (laser-modified) target wave functions, in both the initial and final states. A detailed account is also given of the techniques we have used to evaluate the scattering amplitudes. In addition to a nonperturbative approach (valid to all orders in the laser-projectile interaction), we also discuss a second-order treatment in the combined electron-atom and laser-system (electron plus atom) interactions. The influence of the laser parameters (frequency, intensity, and direction of polarization) on the angular distribution of the ejected electron is discussed, and a number of illustrative examples are given. The structure of the triple differential cross section in the vicinity of resonances is also analyzed.