Laser fusion experiments, facilities, and diagnostics at Lawrence Livermore National Laboratory

• Published in: Applied optics (2004) 1981-06, Vol.20 (11), p.1902-1924
• Main Author: Ahlstrom, H G
• Format: Article
• Language: English
• ISSN: 1559-128X
• DOI: 10.1364/AO.20.001902

The progress of the LLNL Laser Fusion Program in our work to achieve high gain thermonuclear microex-plosions is discussed. Many experiments have been successfully performed and diagnosed using the large complex twenty-beam 30-TW Shiva laser system. A 400-kJ design of the twenty-beam Nova laser has been completed. The construction of the first phase of this facility has begun. The first phase of this Nd-doped low nonlinear index glass laser will consist of ten beams producing 100 kJ in 1-nsec pulses. One beam of the Argus laser has been converted to operation at 532 nm with 10-cm aperture. It will soon operate at 355 nm, also at 10-cm aperture. Frequency conversion crystals are being procured for full aperture operation at either 532 or 355 nm for both Argus beams. We also discuss new diagnostic instruments which provide us with new and improved resolution, information on laser absorption and scattering, thermal energy flow, supra-thermal electrons and their effects, and final fuel conditions. We have made measurements on the absorption and Brillouin scattering for target irradiations at both 1.064 microm and 532 nm. These measurements confirm the expected increased absorption and reduced scattering at the shorter wavelength. Additional data have been obtained on the angular distribution of suprathermal x rays, which further confirms our observation of its nonisotropy. However, we do not yet have an explanation of the phenomena. Implosion experiments have been performed which have produced final fuel densities over the 10-100x range liquid deuterium-tritium (DT) density. The 100x achievement is the highest yet achieved in laser fusion DT fuel targets.