Electron spin polarization in realistic trajectories around the magnetic node of two counter-propagating, circularly polarized, ultra-intense lasers

TL;DR

This paper confirms that counter-propagating ultra-intense circularly polarized lasers can induce electron spin polarization at the magnetic node, accounting for realistic electron trajectories and their effects on polarization stability.

Contribution

It provides a more realistic model of electron trajectories, showing the robustness and temporal limits of laser-induced electron spin polarization.

Findings

Spin polarization differs by ~5% between initial states.

Trajectory instability causes spin precession and limits polarization duration.

Electron dynamics are weakly affected by radiated power variation.

Abstract

It has recently been suggested that two counter-propagating, circularly polarized, ultra-intense lasers can induce a strong electron spin polarization at the magnetic node of the electromagnetic field that they setup. We confirm these results by considering a more sophisticated description that integrates over realistic trajectories. The electron dynamics is weakly affected by the variation of power radiated due to the spin polarization. The degree of spin polarization differs by approximately 5\% if considering electrons initially at rest or already in a circular orbit. The instability of trajectories at the magnetic node induces a spin precession associated with the electron migration that establishes an upper temporal limit to the polarization of the electron population of about one laser period.