Scaling of laser-driven ion energies in the relativistic transparent regime

TL;DR

This paper presents a systematic study of how laser intensity affects ion energies in relativistic transparency, revealing a steep linear scaling and an optimal target thickness, enabling ions exceeding 100MeV/amu with current lasers.

Contribution

It introduces a new scaling law for ion energies in the relativistic transparent regime, validated by simulations and experiments, advancing laser-driven ion acceleration understanding.

Findings

Steep linear scaling of ion energy with normalized laser amplitude a0.

Identification of an optimal target thickness related to relativistic transparency.

Potential to achieve ion energies over 100MeV/amu with existing laser systems.

Abstract

Laser-driven ions have compelling properties and their potential use for medical applications has attracted a huge global interest. One of the major challenges of these applications is generating beams of the required energies. To date, there has been no systematic study of the effect of laser intensity on the generation of laser-driven ions from ultrathin foils during relativistic transparency. Here we present a scaling for ion energies with respect to the on-target laser intensity and in considering target thickness we find an optimum thickness closely related to the experimentally observed relativistic transparency. A steep linear scaling with the normalized laser amplitude a0 has been measured and verified with PIC simulations. In contrast to TNSA, this scaling is much steeper and has been measured for ions with Z > 1. Following our results, ion energies exceeding 100MeV/amu are already accessible with currently available laser systems enabling realization of numerous advanced applications