Time evolution of transient plasma states from nanowire arrays irradiated at relativistic intensities

O S Humphries,C R D Brown,L M R Hobbs,M G Ramsay,B Williams,S M Vinko,M P Hill,D J Hoarty,S F James,P Allan

doi:10.1038/s42005-020-00438-7

O S Humphries, C R D Brown + Show 8 more

Open Access

https://doi.org/10.1038/s42005-020-00438-7

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Abstract

Understanding the evolution of extreme states of matter driven by relativistic laser-plasma interactions is a fundamental problem in high-field physics. This is especially true for nanostructured targets, where hydrodynamic effects play a key role within the ultra-fast time scale of laser absorption. Nanowire array targets are of particular interest as they provide an efficient means to access the ultra-high-energy-density regime due to their increased optical absorption, and have been shown to act as very efficient x-ray emission sources. Here we present analysis of time-resolved x-ray emission spectroscopy from petawatt-irradiated Nickel nanowire arrays, used to characterise the conditions achieved when scaling the performance of nanowire targets to relativistic intensities. A full time evolution of the plasma conditions is extracted from the experimental data, and shows good agreement with the physical interaction picture developed by prior computational studies.

Highlights

Understanding the evolution of extreme states of matter driven by relativistic laser-plasma interactions is a fundamental problem in high-field physics
Nanowire array targets have demonstrated increases in X-ray emission intensity of up to 50× when compared to flat foils[9,24,25], and the improved lasertarget energy coupling can lead to energy densities of 2 GJ cm−3, comparable to those reached in inertial confinement fusion (ICF) implosions
The laser was incident at 25∘ from normal, and spectra were collected on a curved germanium crystal spectrometer coupled to an ultrafast Xray streak camera for an ultrafast X-ray streaked spectrometer

Summary

Introduction

Understanding the evolution of extreme states of matter driven by relativistic laser-plasma interactions is a fundamental problem in high-field physics. There are a very limited number of studies detailing time-resolved plasma dynamics of solid targets resulting from ultrashort relativistic laser interaction[13,14,15], and the evolution of these systems at kilojoule-scale facilities has been unexplored experimentally[16].

Results

Conclusion