# Radiation back-reaction in relativistically strong and QED-strong laser fields

## TL;DR

This paper analyzes electron emission in ultra-strong laser fields, revealing how QED effects modify radiation and deriving the radiation force from quantum principles for the first time.

## Contribution

It introduces a QED-based derivation of the radiation force in relativistically strong laser fields, extending the understanding of electron dynamics in such regimes.

## Key findings

- QED effects modify electron emission at intensities ≥ 10^{22} W/cm^2
- Radiation force derived from QED principles applicable in QED-strong fields
- Electron energy threshold for QED effects is around 1 GeV

## Abstract

The emission from an electron in the field of a relativistically strong laser pulse is analyzed. At the pulse intensities of \ge 10^{22} W/cm^2 the emission from counter-propagating electrons is modified by the effects of Quantum ElectroDynamics (QED), as long as the electron energy is sufficiently high: E \ge 1 GeV. The radiation force experienced by an electron is for the first time derived from the QED principles and its applicability range is extended towards the QED-strong fields.