Laser Wakefield Acceleration Using Wire Produced Double Density Ramps

TL;DR

This paper introduces a new method for electron injection in laser wakefield acceleration using a wire to create density ramps, significantly improving beam charge, quality, and divergence control.

Contribution

It presents a novel wire-based technique to control plasma density profiles, enhancing electron injection and acceleration in LWFA compared to traditional methods.

Findings

Beam charge increased by up to ten times.

Electron beam divergence reduced by approximately 25%.

Spectral spread limited to a few percent.

Abstract

A novel approach to implement and control electron injection into the accelerating phase of a laser wakefield accelerator (LWFA) is presented. It utilizes a wire, which is introduced into the flow of a supersonic gas jet creating shock waves and three regions of differing plasma electron density. If tailored appropriately, the laser plasma interaction takes place in three stages: Laser self-compression, electron injection and acceleration in the second plasma wave period. Compared to self-injection by wavebreaking of a nonlinear plasma wave in a constant density plasma, this scheme increases beam charge by up to one order of magnitude in the quasi-monoenergetic regime. Electron acceleration in the second plasma wave period reduces electron beam divergence by approximately 25 %, and the localized injection at the density downramps results in spectra with less than a few percent relative spread.