High quality GeV proton beams from a density-modulated foil target

TL;DR

This study demonstrates that a density-modulated foil target irradiated by a high-intensity circularly polarized laser can produce quasi-monoenergetic, well-collimated GeV proton beams with high efficiency, as shown by multi-dimensional PIC simulations.

Contribution

The paper introduces a novel density-modulated foil target design that enhances proton acceleration efficiency and beam quality in laser-driven proton acceleration.

Findings

Protons reach up to 1.4 GeV energy.

Proton beams are well collimated with less than 4° divergence.

High energy conversion efficiency from laser to protons.

Abstract

We study proton acceleration from a foil target with a transversely varying density using multi-dimensional Particle-in-Cell (PIC) simulations. In order to reduce electron heating and deformation of the target, circularly polarized Gaussian laser pulses at intensities of the order of 1022Wcm-2 are used. It is shown that when the target density distribution fits that of the laser intensity profile, protons accelerated from the center part of the target have quasi-monoenergetic spectra and are well collimated. In our two-dimensional PIC simulations, the final peak energy can be up to 1.4 GeV with the full-width of half maximum divergence cone of less than 4o. We observe highly efficient energy conversion from the laser to the protons in the simulations.