Current status and highlights of the ELI-NP research program

The emergence of a new era reaching beyond current state-of-the-art ultrashort and ultraintense laser technology has been enabled by the approval of around V 850 million worth of structural funds in 2011–2012 by the European Commission for the installation of Extreme Light Infrastructure(ELI).The ELI project consists of three pillars being built in the Czech Republic,Hungary,and Romania.This challenging proposal is based on recent technical progress allowing ultraintense laser fields in which intensities will soon be reaching as high as I0∼1023Wcm−2.This tremendous technological advance has been brought about by the invention of chirped pulse amplification by Mourou and Strickland.Romania is hosting the ELI for Nuclear Physics(ELI-NP)pillar in M˘agurele near Bucharest.The new facility,currently under construction,is intended to serve the broad national,European,and international scientific community.Its mission covers scientific research at the frontier of knowledge involving two domains.The first is laser-driven experiments related to NP,strong-field quantum electrodynamics,and associated vacuum effects.The second research domain is based on the establishment of a Compton-backscattering-based,high-brilliance,and intenseγbeam with Eγ≲19.5 MeV,which represents a merger between laser and accelerator technology.This system will allow the investigation of the nuclear structure of selected isotopes and nuclear reactions of relevance,for example,to astrophysics with hitherto unprecedented resolution and accuracy.In addition to fundamental themes,a large number of applications with significant societal impact will be developed.The implementation of the project started in January 2013 and is spearheaded by the ELI-NP/Horia Hulubei National Institute for Physics and Nuclear Engineering(IFIN-HH).Experiments will begin in early 2020.

Detailed characterization of a laboratory magnetized supercritical collisionless shock and of the associated proton energization

Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of nonthermal particles and high-energy radiation.In the absence of particle collisions in the system,theory shows that the interaction of an expanding plasma with a pre-existing electromagnetic structure(as in our case)is able to induce energy dissipation and allow shock formation.Shock formation can alternatively take place when two plasmas interact,through microscopic instabilities inducing electromagnetic fields that are able in turn to mediate energy dissipation and shock formation.Using our platform in which we couple a rapidly expanding plasma induced by high-power lasers(JLF/Titan at LLNL and LULI2000)with high-strength magnetic fields,we have investigated the generation of a magnetized collisionless shock and the associated particle energization.We have characterized the shock as being collisionless and supercritical.We report here on measurements of the plasma density and temperature,the electromagnetic field structures,and the particle energization in the experiments,under various conditions of ambient plasma and magnetic field.We have also modeled the formation of the shocks using macroscopic hydrodynamic simulations and the associated particle acceleration using kinetic particle-in-cell simulations.As a companion paper to Yao et al.[Nat.Phys.17,1177–1182(2021)],here we show additional results of the experiments and simulations,providing more information to allow their reproduction and to demonstrate the robustness of our interpretation of the proton energization mechanism as being shock surfing acceleration.