Implementation of gas target on the LIL facility

The main goal of gas target filling is to provide, for post shot analysis, a precise measurement of the pressure and the right composition of gas in the millimeter sized hohlraum as close as possible (typically a minute before) to shot time. The purpose of this paper is to present how gas-containing targets will be implemented on the LIL facility. The two chosen solutions are described here

Hypervelocity impacts into porous graphite: Experiments and simulations

We present experiments and numerical simulations of hypervelocity impacts of 0.5mm steel spheres into graphite, for velocities ranging between 1100 and 4500ms?1. Experiments have evidenced that, after a particular striking velocity, depth of penetration no longer increases but decreases. Moreover, the projectile is observed to be trapped below the crater surface. Using numerical simulations, we show how this experimental result can be related to both materials, yield strength. A Johnson-Cook model is developed for the steel projectile, based on the literature data. A simple model is proposed for the graphite yield strength, including a piecewise pressure dependence of the Drucker-Prager form, which coefficients have been chosen to reproduce the projectile penetration depth. Comparisons between experiments and simulations are presented and discussed. The damage properties of both materials are also considered, by using a threshold on the first principal stress as a tensile failure criterion. An additional compressive failure model is also used for graphite when the equivalent strain reaches a maximum value. We show that the experimental crater diameter is directly related to the graphite spall strength. Uncertainties on the target yield stress and failure strength are estimated

Overview of on-going LIL experiments

The Ligne d'Integration Laser (LIL) facility has been designed as a prototype for the Laser MegaJoule (LMJ) which is a cornerstone of the French 'Simulation Program'. This laser has been intensively used to test and improve the LMJ components. In addition, a large panel of plasma diagnostics has been installed and is currently used to perform laser-plasma experiments. After a brief discussion about the LIL design, we present the last results in various plasma physics domains.</p

Overview of on-going LIL experiments

The Ligne d'Integration Laser (LIL) facility has been designed as a prototype for the Laser MegaJoule (LMJ) which is a cornerstone of the French 'Simulation Program'. This laser has been intensively used to test and improve the LMJ components. In addition, a large panel of plasma diagnostics has been installed and is currently used to perform laser-plasma experiments. After a brief discussion about the LIL design, we present the last results in various plasma physics domains.</p