Future for inertial-fusion energy in Europe:a roadmap

The recent achievement of fusion ignition with laser-driven technologies at the National Ignition Facility sets a historic accomplishment in fusion energy research.This accomplishment paves the way for using laser inertial fusion as a viable approach for future energy production.Europe has a unique opportunity to empower research in this field internationally,and the scientific community is eager to engage in this journey.We propose establishing a European programme on inertial-fusion energy with the mission to demonstrate laser-driven ignition in the direct-drive scheme and to develop pathway technologies for the commercial fusion reactor.The proposed roadmap is based on four complementary axes:(ⅰ)the physics of laser-plasma interaction and burning plasmas;(ⅱ)high-energy high repetition rate laser technology;(ⅲ)fusion reactor technology and materials;and(ⅳ)reinforcement of the laser fusion community by international education and training programmes.We foresee collaboration with universities,research centres and industry and establishing joint activities with the private sector involved in laser fusion.This project aims to stimulate a broad range of high-profile industrial developments in laser,plasma and radiation technologies along with the expected high-level socio-economic impact.

Petawatt and exawatt class lasers worldwide

In the 2015 review paper‘Petawatt Class Lasers Worldwide’a comprehensive overview of the current status of highpower facilities of>200 TW was presented.This was largely based on facility specifications,with some description of their uses,for instance in fundamental ultra-high-intensity interactions,secondary source generation,and inertial confinement fusion(ICF).With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification(CPA),which made these lasers possible,we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed.We are now in the era of multi-petawatt facilities coming online,with 100 PW lasers being proposed and even under construction.In addition to this there is a pull towards development of industrial and multi-disciplinary applications,which demands much higher repetition rates,delivering high-average powers with higher efficiencies and the use of alternative wavelengths:mid-IR facilities.So apart from a comprehensive update of the current global status,we want to look at what technologies are to be deployed to get to these new regimes,and some of the critical issues facing their development.

A history of high-power laser research and development in the United Kingdom

The first demonstration of laser action in ruby was made in 1960 by T.H.Maiman of Hughes Research Laboratories,USA.Many laboratories worldwide began the search for lasers using different materials,operating at different wavelengths.In the UK,academia,industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications.This historical review looks at the contribution the UK has made to the advancement of the technology,the development of systems and components and their exploitation over the last 60 years.

First radiative shock experiments on the SG-II laser

We report on the design and first results from experiments looking at the formation of radiative shocks on the ShenguangII(SG-II)laser at the Shanghai Institute of Optics and Fine Mechanics in China.Laser-heating of a two-layer CH/CH–Br foil drives a∼40 km/s shock inside a gas cell filled with argon at an initial pressure of 1 bar.The use of gas-cell targets with large(several millimetres)lateral and axial extent allows the shock to propagate freely without any wall interactions,and permits a large field of view to image single and colliding counter-propagating shocks with time-resolved,pointprojection X-ray backlighting(∼20µm source size,4.3 keV photon energy).Single shocks were imaged up to 100 ns after the onset of the laser drive,allowing to probe the growth of spatial nonuniformities in the shock apex.These results are compared with experiments looking at counter-propagating shocks,showing a symmetric drive that leads to a collision and stagnation from∼40 ns onward.We present a preliminary comparison with numerical simulations with the radiation hydrodynamics code ARWEN,which provides expected plasma parameters for the design of future experiments in this facility.