High-energy-density plasma in femtosecond-laser-irradiated nanowire array targets for nuclear reactions

TL;DR

This study investigates high-energy-density plasmas generated by femtosecond laser-irradiated nanowire arrays, revealing enhanced ion acceleration and energy densities, with experimental validation of neutron and proton emissions relevant for nuclear reactions.

Contribution

It introduces a combined numerical and experimental analysis of nanowire array targets, demonstrating significantly increased ion energy densities and energy conversion efficiency compared to planar targets.

Findings

Ion energy density is an order of magnitude higher than planar targets.

Up to 8% of laser energy converts to confined protons.

Neutron and proton emissions confirm high-energy-density plasma generation.

Abstract

In this work, the high-energy-density plasmas (HEDP) evolved from joule-class-femtosecond-laser-irradiated nanowire array (NWA) targets are numerically and experimentally studied. The particle-in-cell (PIC) simulations indicate that ions accelerated in the sheath field around the nanowires' surface were eventually confined in NWA plasma, contributing most to the high energy densities. The protons emitted from the front surface of targets provide rich information about the interaction. The electron and ion energy densities in a broad target parameter range are given. Compared to planar targets, the ion energy density is one order of magnitude higher, and the volume of the HEDP is several-fold larger. At optimal target parameters, 8% of the laser energy can be converted to confined protons and results in ion energy densities of up to GJ/cm3 level. Experimental measurements of the emitted ions and neutrons from 2H(d, n)3He fusion from polyethylene and deuterated polyethylene NWA targets confirm the above results.