Bunched proton acceleration from a laser-irradiated cone target

TL;DR

This paper demonstrates a novel laser-irradiated cone target scheme that produces high-energy, low-spread proton beams with potential applications in medicine and research, using 3D particle-in-cell simulations.

Contribution

The study introduces a new cone target configuration that significantly enhances proton acceleration efficiency and beam quality compared to previous methods.

Findings

Protons reach hundreds of MeV energy with ~2% energy spread.

High bunching acceleration fields up to tens of TV/m are generated.

The scheme shows robustness across various laser and target parameters.

Abstract

Laser-driven ion acceleration is an attractive technique for compact high-energy ion sources. Currently, among various physical and technical issues to be solved, the boost of ion energy and the reduction of energy spread represent the key challenges with this technique. Here we present a scheme to tackle these challenges by using a hundred-terawatt-class laser pulse irradiating a cone target. Three-dimensional particle-in-cell simulations show that a large number of electrons are dragged out of the cone walls and accelerated to hundreds of MeV by the laser fields inside the cone. When these energetic dense electron beams pass through the cone target tip into vacuum, a very high bunching acceleration field, up to tens of TV/m, quickly forms. Protons are accelerated and simultaneously bunched by this field, resulting in quasi-monoenergetic proton beams with hundred MeV energy and low energy spread of ~2%. Results exploring the scaling of the proton beam energy with laser and target parameters are presented, indicating that the scheme is robust. This opens a new route for compact high-energy proton sources from fundamental research to biomedical applications.