Strengths and weaknesses of KrF lasers for inertial confinement fusion applications learned from the AURORA laser

Abstract

The AURORA KrF laser at Los Alamos became operational in August 1989. AURORA is the first integrated system for demonstrating the capability of a KrF laser to perform target physics experiments for inertial confinement fusion (ICF) and is currently configured as a 5-kJ, 5-ns, 96-beam device. Both laser physics and ICF target physics experiments have been performed over the last year. Of the four major amplifiers in the AURORA laser system, one performed better than expected, one performed about as expected, and two performed below expectations. The causes of the variability in the amplifier performance are now well enough understood that this information can be used to improve the detailed design of the NIKE laser currently under construction at the Naval Research Laboratory. design of the NIKE laser currently under construction at the Naval Research Laboratory. High-dynamic-range pulse shapes have been propagated with minimal distortion through the AURORA amplifier chain, verifying theoretical predictions. Target physics experiments have been performed with intensities greater than 100 TW/cm2, pulse lengths ranging from 2–7 ns, and spot-size diameters from 500–1100 µm. The analysis of this first-generation kJ-class KrF laser target physics facility identified the strengths and weaknesses of KrF lasers for ICF applications. Detailed measurements of amplifier performance led to a better understanding of issues for KrF laser-fusion systems, and design studies for future KrF lasers for ICF applications incorporate improvements based in part on AURORA experience.