First radiative shock experiments on the SG-II laser

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.

ELI Gammatron Beamline: A Dawn of Ultrafast Hard X-ray Science

“…(c) Subsurface probing of high-energy-density (HED) state materials: The laser-driven shock wave is an efficient way to generate dynamic high pressure for exploring the dynamical strengths of materials. Shocks are important in various fields of research, such as condensed matter physics, nuclear fusion, HED science [69][70][71][72], and laboratory astrophysics [73,74], as they provide the ability to test the extreme conditions of matter in terms of both pressure and temperature. This is extremely important in inertial confinement fusion research, where a series of shocks compress the fuel and capsules.…”

Study of radiative shocks using 2D interferometry and XUV spectroscopy

“…9,[23][24][25][26] They are considered as a test case of coupling between radiation and hydrodynamic, [27][28][29][30] which in turn need to be tested against dedicated experiments. In addition to a few experiments performed on electric pulsed power installations, [31][32][33] the majority of the experiments have been performed on high energy nanosecond laser installations, 11,[34][35][36][37][38][39][40][41][42] with laser intensity on the target of about 10 14 W/cm 2 . As radiative effects increase with the Mach number, most experiments have been performed in heavy gases like Xenon, at various initial pressures, where typical shock velocities are in the range of 50 km/s and are analyzed over a few nanoseconds.…”

Post-treatment of 351 nm SiO2 antireflective coatings for high power laser systems prepared by the sol-gel method

“…The sol-gel method, which was first, to the best of our knowledge, described by Ebelmen in 1846, has since been widely used to prepare different kinds of materials [1] . Porous silica antireflective (AR) coatings prepared using the sol-gel method possess excellent optical properties and superior laser-induced damage thresholds (LIDTs) and are typically used in final optics assemblies of inertial confinement fusion (ICF) experimental devices such as the National Ignition Facility (NIF) in the USA [2] , Laser Mégajoule (LMJ) in France [3] , and Shenguang facilities (SGs) in China [4][5][6][7] . Silicon oxide coatings with low refractive indices and prepared using the sol-gel method can be used for fused silica and crystal elements in final optics assemblies, while hafnium oxide and tantalum oxide coatings with high refractive indices can be used in reflective elements [8][9][10] .…”