Dynamical spin effects in ultra-relativistic laser pulses

TL;DR

This paper explores how electron spin influences their motion in ultra-relativistic laser fields, revealing significant spin-dependent effects that could be observed experimentally with current laser technology.

Contribution

It introduces a classical theory demonstrating the impact of spin forces on electron dynamics in ultra-relativistic laser pulses, including spin-dependent transverse momentum acquisition.

Findings

Spin forces alter electron trajectories in ultra-relativistic fields.

Electron deflection depends on laser intensity, pulse duration, and initial spin.

Particle-in-cell simulations support the theoretical predictions.

Abstract

The dynamics of single laser-driven electrons and many particle systems with spin are investigated on the basis of a classical theory. We demonstrate that the spin forces can alter the electron dynamics in an ultra-relativistic laser field due to the coupling of the electron's spin degree of freedom to its kinematic momentum. High-energy electrons can acquire significant spin-dependent transverse momenta while passing through a counterpropagating ultra-relativistic infrared laser pulse. Numerical calculations show that the deflection of the electrons by the laser pulse is determined by the laser intensity, the pulse duration, and the initial spin orientation of the electron. We complement our investigation of these dynamical spin effects by performing particle-in-cell simulations and point out possibilities of an experimental realization of the predicted effect with available laser parameters.