Coulomb driven energy boost of heavy ions for laser plasma acceleration

TL;DR

This paper demonstrates a significant increase in the kinetic energy of heavy ions accelerated by laser pulses, achieved through a novel understanding of ionization effects and a new theoretical model.

Contribution

It introduces a new theoretical model explaining how spatial ionization dependence enhances heavy ion acceleration in laser plasma interactions.

Findings

Gold ions reach >200 MeV energy levels.

Ionization-dependent electric fields boost ion acceleration.

Theoretical model explains energy enhancement mechanism.

Abstract

An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultra thin gold foils have been irradiated by an ultra short laser pulse at an intensity of $6\times 10^{19}$ W/cm$^{2}$. Highly charged gold ions with kinetic energies up to $> 200$ MeV and a bandwidth limited energy distribution have been reached by using $1.3$ Joule laser energy on target. $1$D and $2$D Particle in Cell simulations show how a spatial dependence on the ions ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a varying charge density along the target normal and is capable of explaining the energy boost of highly charged ions, leading to a higher efficiency in laser acceleration of heavy ions.