Forward sliding-swing acceleration: electron acceleration by high-intensity lasers in strong plasma magnetic fields

TL;DR

This paper introduces a novel electron acceleration mechanism called forward sliding-swing acceleration, driven by high-intensity lasers in strong plasma magnetic fields, achieving high energies with threshold behavior rather than resonance.

Contribution

It presents a new acceleration mechanism enabled by strong plasma magnetic fields, with analytical modeling and numerical validation showing significant energy gains.

Findings

Electrons reach energies two orders of magnitude higher with magnetic fields.

The mechanism operates above a threshold current, not relying on resonance.

Analytical relations link current, initial momentum, and energy gain.

Abstract

A high-intensity laser beam propagating through a dense plasma drives a strong current that robustly sustains a strong quasi-static Mega Tesla-level azimuthal magnetic field. The transverse laser field efficiently accelerates electrons in the presence of such a field that confines the transverse motion and deflects the electrons in the forward direction, establishing the novel forward-sliding swing acceleration mechanism. Its advantage is a threshold rather than resonant behavior, accelerating electrons to high energies for sufficiently strong laser-driven currents. We study the electrons' dynamics by a simplified model analytically, specifically deriving simple relations between the current, the particles' initial transverse momenta and the laser's field strength classifying the energy gain. We confirm the model's predictions by numerical simulations, indicating Mega ampere-level threshold currents and energy gains two orders of magnitude higher than achievable without the magnetic field.