Shock dynamics and shock collision in foam layered targets

K Batani,W Nazarov,M Pfeifer,A Amirova,J Skala,R Dudzak,R Dezulian,E Krousky,D Batani,R Benocci,A Aliverdiev

doi:10.1017/hpl.2021.33

Abstract

Abstract We present an experimental study of the dynamics of shocks generated by the interaction of a double-spot laser in different kinds of targets: simple aluminum foils and foam–aluminum layered targets. The experiment was performed using the Prague PALS iodine laser working at 0.44 μm wavelength and irradiance of a few 1015 W/cm2. Shock breakouts for pure Al and for foam-Al targets have been recorded using time-resolved self-emission diagnostics. Experimental results have been compared with numerical simulations. The shocks originating from two spots move forward and expand radially in the targets, finally colliding in the intermediate region and producing a very strong increase in pressure. This is particularly clear for the case of foam layered targets, where we also observed a delay of shock breakout and a spatial redistribution of the pressure. The influence of the foam layer doped with high-Z (Au) nanoparticles on the shock dynamics was also studied.

Highlights

The study of shock dynamics and shock collision in lasergenerated plasmas has recently received much attention in the scientific literature
In this way we have identified several effects in foam layered targets as compared with simple Al foils: (i) the shock breakout was delayed with respect to Al foils, (ii) the pressure distribution had a different spatial profile, and (iii) we obtained experimental evidence of collision between shocks producing a strong increase in pressure
The results obtained in foam–Al targets show several interesting effects, namely: (i) delay of shock breakout time, (ii) spatial redistribution of pressure, (iii) increase in shock breakout time when the laser energy is increased, and (iv) evidence of collision between the two shocks

Summary

Introduction

The study of shock dynamics and shock collision in lasergenerated plasmas has recently received much attention in the scientific literature. Collisionless shocks in plasmas, are important in many astrophysical events and, with the recent advances in ultrahigh-intensity lasers, can be investigated in laboratory environments. They are important as origin of particle acceleration in the astrophysical context and they are relevant to the study of laser-driven particle. The shock ignition approach[18,19] is largely based on the pressure amplification following the collision of an igniting shock, with the shock formed by the compression beams reflected at the target center In this context, we have realized an experiment to investigate the compression dynamics induced by double shocks created by two separate laser spots focused on simple aluminum foils or on layered foam/aluminum targets. In this way we have identified several effects in foam layered targets as compared with simple Al foils: (i) the shock breakout was delayed with respect to Al foils, (ii) the pressure distribution had a different spatial profile, and (iii) we obtained experimental evidence of collision between shocks producing a strong increase in pressure

Methods

Results

Conclusion