Search

We present an overview of recent experiments fielded on the LIL facility. A key issue for mega-joule class laser facilities is shrapnel fragment generation. A specific collector was therefore developed to capture debris in aerogel and dedicated shots were done to quantitatively evaluate target fragmentation phenomena. The LIL panel of transmitted and backscattered light diagnostics is well suited for laser-plasma interaction (LPI) experiments. This include gas-filled hohlraum configurations relevant to Indirect Drive ignition targets in order to test the specific LMJ longitudinal SSD technique, as well as LPI experiments with foam targets for laser beam smoothing in underdense plasma in the context of Direct Drive. After Visar commissioning a campaign was dedicated to boron Equation of State (EOS).

Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002 [1, 2], experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used [3, 4]. We present experimental results and comparisons with numerical simulations.

This paper presents experimental results obtained at LULI 2000 and LIL about (i) the compared laser plasma coupling at 526 (2ω) and 351 nm (3ω) and (ii) the early laser imprint suppression using foam targets as plasma smoother of the laser beam. Both experiments are described, part of the experimental results are presented and discussed.

Feasability of efficient X-ray sources for LMJ (LaserMegaJoule) targets radiography in the multi-keV/ns regime was demonstrated on OMEGA laser facility (University of Rochester) from 2002 to 2004 [1][2][3]. We significantly enhanced the conversion efficiency of titanium, copper and germanium foils using an optimized prepulse/pulse combination [4]. Since higher X-ray energy and therefore high electronic temperature require more confinement, we built and successfully tested in 2005, plastic cylindrical hohlraums internally coated with titanium in various OMEGA beam configurations, pulse types (with and without prepulse) and target designs. The conversion efficiency (CE), depends on hohlraum length and diameter and the highest CE was measured above 17%, which is better than any other x-ray sources in this photon energy range (i.e. 4.7 keV). The best experimental setup was a 2-cone irradiation scheme without prepulse i.e. the simplest and the most economic configuration in view of radiographic purposes. These studies were carried on in february 2007 with Ge-lined hohlraums and Ti-lined halfraums. We describe and show comparisons between experimental results (time integrated and resolved x-ray imaging, pinholes and x-ray diode) with 2D hydrorad simulations.