Applications of a Rayleigh-Taylor model to direct-drive laser fusion

Abstract

This paper presents a simple physics-based model for the interpretation of key metrics in laser direct drive. The only input parameters required are target scale, in-flight aspect ratio, and beam-to-target radius, and the importance of each has been quantified with a tailored set of cryogenic implosion experiments. These analyses lead to compact and accurate predictions of the fusion yield and areal density as a function of hydrodynamic stability, and they suggest new ways to take advantage of direct drive. To provide examples, we discuss how the inferred mix width behaves relative to theory and then show how it could be exploited to perform a direct drive implosion with a Lawson metric or χ_{noα} of 0.24±0.02-using a novel parameter space at high velocities and beam radii on the OMEGA laser-that projects to ignition at a laser energy of ≤2.0 MJ.