First radiative shock experiments on the SG-II laser

F Suzuki‐Vidal ,Mingying Sun,Uddhab Chaulagain,Lei Ren,Carolyn Kuranz,Thomas Clayson,Teodora Mihailescu,Huiya Liu,Ning Kang,Manuel Cotelo,Carolina De Almeida Rossi,Jianqiang Zhu,J W D Halliday ,C Spindloe ,J M Foster ,C Danson ,J P Chittenden ,Bin Zhu ,P Velarde ,C Stehlé

doi:10.1017/hpl.2021.17

Abstract

Abstract We report on the design and first results from experiments looking at the formation of radiative shocks on the Shenguang-II (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 $\sim 40$ 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, point-projection X-ray backlighting ( $\sim 20$ μm 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 $\sim 40$ 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.

Highlights

Radiative shocks are formed when radiative losses from the shock can modify its structure
Results from single and colliding radiative shock experiments are presented in Figures 3(a) and 3(b), respectively
We have presented the first results from experiments looking at the formation of radiative shocks in argon with pistondriven gas cells on the SG-II laser

Summary

Introduction

Radiative shocks are formed when radiative losses from the shock can modify its structure. This occurs when the radiative energy flux is comparable to the kinetic energy flux at the shock front. In this regime, radiation can modify both the pre- and post-shock regions. Radiative effects increase with the shock speed due to stronger post-shock heating and, in a first approximation for typical experimental conditions, Recent works have looked at bridging the gap between experiments and theory/numerical simulations of radiative

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Conclusion