Multidimensional effects on proton acceleration using high-power intense laser pulses

TL;DR

This paper investigates how the dimensionality of simulations affects proton acceleration in laser-target interactions, providing an empirical ratio to estimate 3D proton energies from 2D simulation results, applicable to structured targets.

Contribution

It introduces an empirical ratio between 2D and 3D simulation results for proton energies in TNSA, aiding realistic energy estimations from simpler simulations.

Findings

3D proton energies are significantly lower than 2D results.

An empirical ratio between 2D and 3D energies is established.

The scaling law applies to structured targets.

Abstract

Dimensional effects in particle-in-cell (PIC) simulation of target normal sheath acceleration (TNSA) of protons are considered. As the spatial divergence of the laser-accelerated hot sheath electrons and the resulting space-charge electric field on the target backside depend on the spatial dimension, the maximum energy of the accelerated protons obtained from three-dimensional (3D) simulations is usually much less that from two-dimensional (2D) simulations. By closely examining the TNSA of protons in 2D and 3D PIC simulations, we deduce an empirical ratio between the maximum proton energies obtained from the 2D and 3D simulations. This ratio may be useful for estimating the maximum proton energy in realistic (3D) TNSA from the results of the corresponding 2D simulation. It is also shown that the scaling law also applies to TNSA from structured targets.