Electron-Angular-Distribution Reshaping in Quantum Radiation-Dominated Regime

TL;DR

This paper investigates how quantum stochastic effects alter the angular distribution of electrons after intense laser interactions, revealing a peak structure indicative of quantum radiation effects, distinguishable from classical predictions.

Contribution

It demonstrates that quantum stochastic photon emission causes electron aggregation along the laser axis, producing a distinctive peak in angular distribution, a novel quantum signature.

Findings

Electron distribution shifts from ring to peak structure due to quantum effects.

The peak structure is robust and observable with current technology.

Quantum stochasticity fundamentally alters electron dynamics in intense laser fields.

Abstract

Dynamics of an electron beam head-on colliding with an ultraintense focused ultrashort circularly-polarized laser pulse are investigated in the quantum radiation-dominated regime. Generally, the ponderomotive force of the laser fields may deflect the electrons transversely, to form a ring structure on the cross-section of the electron beam. However, we find that when the Lorentz factor of the electron $\gamma$ is approximately one order of magnitude larger than the invariant laser field parameter $\xi$, the stochastic nature of the photon emission leads to electron aggregation abnormally inwards to the propagation axis of the laser pulse. Consequently, the electron angular distribution after the interaction exhibits a peak structure in the beam propagation direction, which is apparently distinguished from the "ring"-structure of the distribution in the classical regime, and therefore, can be recognized as a proof of the fundamental quantum stochastic nature of radiation. The stochasticity signature is robust with respect to the laser and electron parameters and observable with current experimental techniques.