Towards precision quantitative measurement of radiation reaction within the classical radiation-dominated regime

TL;DR

This paper proposes a new experimental setup using high-intensity lasers and electron beams to precisely measure radiation reaction effects in the classical radiation-dominated regime, bridging the gap between classical and quantum models.

Contribution

It introduces a novel experimental scenario and identifies key observables to validate radiation reaction models in the classical regime with minimal quantum effects.

Findings

Numerical simulations identify three key observables for RR detection.

The approach enables validation of quantum correction factors.

It provides benchmarks for classical-to-quantum radiation reaction models.

Abstract

Radiation reaction (RR) is a fundamental yet incompletely validated process in laser-particle interactions, since it lacks quantitatively definitive experimental verifications, especially the transition from classical to quantum regime. Herein, we propose a novel experimental scenario for investigating radiation RR within the classical radiation-dominated regime (CRDR), via the collision of a high-intensity petawatt-class laser with a tens-of-MeV electron beam from a LINAC. This approach enables access to a distinct parameter regime wherein RR dominates electron dynamics while quantum effects remain modest. Numerical simulations demonstrate that three key observables exist for identifying the RR within this CRDR regime: (i) quantitative measurement of energy spectra to validate the quantum correction factor; (ii) control of the collision time delay with charge-counting to map intensity dependence of RR; and (iii) verification of large angle ($90^\circ$) photon emission under the recoil condition $2\gamma \gtrsim a_0$. These experimental measurements will establish the benchmarks for RR models spanning the classical-to-quantum regime, thereby providing critical insights into fundamental strong-field quantum electrodynamics.