# Inclusion of Coulomb effects in laser-atom interactions

## TL;DR

This paper explores how Coulomb interactions influence electron dynamics in strong laser fields, revealing effects overlooked by traditional models and proposing improved theoretical approaches for different time scales.

## Contribution

It introduces Coulomb-corrected models that accurately describe short and long time scale phenomena in laser-atom interactions, highlighting the importance of Coulomb effects.

## Key findings

- Coulomb effects are significant even in intense laser fields.
- Coulomb-corrected models improve short-term predictions.
- Guiding center model effectively describes long-term phenomena.

## Abstract

We investigate the role of the Coulomb interaction in strong field processes. We find that the Coulomb field of the ion makes its presence known even in highly intense laser fields, in contrast to the assumptions of the strong field approximation. The dynamics of the electron after ionization is analyzed with four models for an arbitrary laser polarization: the Hamiltonian model in the dipole approximation, the strong field approximation, the Coulomb-corrected strong field approximation and the guiding center. These models illustrate clearly the Coulomb effects, in particular Coulomb focusing and Coulomb asymmetry. We show that the Coulomb-corrected strong field approximation and the guiding center are complementary, in the sense that the Coulomb-corrected strong field approximation describes well short time scale phenomena (shorter than a laser cycle) while the guiding center is well suited for describing long time scale phenomena (longer than a laser cycle) like Coulomb-driven recollisions and Rydberg state creation.