Lorentz force on an electron in a strong plane-wave laser field and the low-frequency limit for ionization

TL;DR

This paper derives an approximate relativistic model for an electron in a plane-wave laser field, analyzes the Lorentz force, and discusses low-frequency ionization effects including nondipole and relativistic influences.

Contribution

It presents a new approximate non-parameter form of the equations of motion for an electron in a plane wave, highlighting relativistic and nondipole effects on ionization.

Findings

Electron follows a 'figure-8' trajectory in a linearly polarized wave.

Numerical calculation of Lorentz force over time.

Discussion of low-frequency ionization effects with relativistic considerations.

Abstract

A motion of a classical free charge in an electromagnetic plane wave can be found exactly in a fully relativistic case. We have found an approximate non-parameter form of the suitable equations of motion. In a linearly polarized wave, in the simplest frame of reference, the charge moves along the well-known "figure-8" path. We have numerically calculated the Lorentz force acting on the charge as a function of time. In virtue of this, for the low frequency ionization (or detachment) rate, we discuss a manifestation of nondipole and relativistic effects.