Enhanced relativistic-electron beam collimation using two consecutive laser pulses

TL;DR

This paper demonstrates a novel double laser pulse technique to improve relativistic electron beam collimation by controlling magnetic fields generated during laser interactions, with experimental validation at the LULI-ELFIE facility.

Contribution

It introduces a new method using two consecutive laser pulses to enhance electron beam collimation through magnetic field manipulation, with detailed experimental analysis.

Findings

Maximum collimation depends on laser focus size ratio.

Collimation effectiveness varies with pulse delay time.

Diagnostic imaging confirms improved beam control.

Abstract

The double laser pulse approach to relativistic electron beam (REB) collimation has been investigated at the LULI-ELFIE facility. In this scheme, the magnetic field generated by the first laser-driven REB is used to guide a second delayed REB. We show how electron beam collimation can be controlled by properly adjusting laser parameters. By changing the ratio of focus size and the delay time between the two pulses we found a maximum of electron beam collimation clearly dependent on the focal spot size ratio of the two laser pulses and related to the magnetic field dynamics. Cu-K alpha and CTR imaging diagnostics were implemented to evaluate the collimation effects on the respectively low energy (< 100 keV) and high energy (> MeV) components of the REB.