Experimental and numerical investigation of laser intensity distribution influence on laser pressure loading

Abstract

Laser shock applications are numerous and various. They all require to know how pressure loading—due to laser irradiation—is influenced by laser parameters. This study aims at analyzing the influence of laser intensity distribution on pressure loading. This work presents the results from laser shots proceeded at LULI2000 on aluminum with LiF window targets. First, laser parameters are introduced and the radial distribution of laser intensity is estimated, thanks to a fourfold Gaussian distribution. Then, the experimental results and post-mortem samples are analyzed. Afterward, two methodologies to estimate the laser pressure loading—considering the laser intensity distribution—are described, applied, and compared. The first one with the monodimensional multi-physics simulation code ESTHER and the second one coupling the use of both ESTHER and the bidimensional (2D) hydrodynamics simulation code HESIONE [Aubert et al., J. Laser Appl. 31, 042014 (2019)]. The discussion presents the accuracy of these two methodologies regarding the experimental results. Comparison with a perfect top-hat laser intensity distribution highlights the edge effects. Finally, future possible works are suggested such as testing the methodology on other laser facilities or using a 2D/3D multi-physics simulation code.