DYMAT 2009 (2009) 163-169
DOI: 10.1051/dymat/2009022

Spallation and microjetting in laser-shock-loaded aluminium and gold

E. Lescoute¹, T. De Rességuier¹, J.-M. Chevalier², M. Boustie¹, L. Berthe³ and J.-P. Cuq-Lelandais<sup>1

1</sup>  Laboratoire de Combustion et de Détonique, UPR 9028 CNRS, ENSMA, 1 Av. Clément Ader, 86961 Futuroscope Cedex, France
²  CEA/CESTA, 15 Av. Sablières BP. 2, 33114 Le Barp, France
³  Laboratoire d'Application des Lasers de Puissance, UPR 1578 CNRS, 94114 Arcueil, France

Published online: 15 September 2009

Abstract
Dynamic fragmentation of shock-loaded metals is an issue of considerable importance for both basic science and a variety of technological applications, such as inertial confinement fusion, which involves high energy laser irradiation of thin metallic shells. In this context, we present an experimental and numerical study of fragmentation and debris ejection in laser shock-loaded aluminium and gold, under both nanosecond and sub-picosecond laser pulses. Such fragmentation is mainly governed by two distinct processes: microjetting, that is ejection of thin jets upon shock breakout at the (rough) free surface, and spall fracture, which occurs upon tensile loading due to wave interactions inside the sample. Experimental results consist of time-resolved velocity measurements, transverse optical shadowgraphy of ejected debris, and post-shock observations of recovered targets. They are compared to numerical computations performed with two hydrocodes, and a correct overall consistency is obtained.

© EDP Sciences 2009