How predictive are THD experiments? Bayesian analysis of the ICF data from the variability campaign

The 1.3 MJ inertial confinement fusion (ICF) experiment at the National Ignition

Facility of August 8, 2021, which is often referred to as being at the threshold of

ignition, has been followed by a series of repeat experiments to evaluate the

robustness of the experimental design. One of the methods that have been

developed to evaluate the variability within this repeatability campaign involves

Bayesian inference of the possible degradation mechanisms for individual

experiments simultaneously with inferring the variability within the entire series.

Meanwhile, a THD (2% deuterium) version of the 1.3 MJ experiment was carried

out on February 20, 2022, to better understand hydrodynamic properties of the

design. In this presentation, we investigate whether the THD experiment, when

included in the Bayesian variability model, provides consistent and/or new

information relative to the series of DT (50% deuterium) experiments. The

ultimate goal is to understand whether low-yield THD shots, which could be

fielded more frequently than the high-yield DT shots, should play a larger role in

designing more robust ICF experiments. LLNL-ABS-836466.