Physics-informed transformation toward improving the machine-learned NLTE models of ICF simulations

The integration of machine-learning techniques into inertial confinement fusion (ICF) simulations has emerged as a powerful approach for enhancing computational efficiency. By replacing the costly nonlocal thermodynamic equilibrium (NLTE) model with machine-learning models, significant reductions in calculation time have been achieved. However, determining how to optimize machine-learning-based NLTE models in order to match ICF simulation dynamics remains challenging, underscoring the need for physically relevant error metrics and strategies to enhance model accuracy with respect to these metrics. Thus, we propose novel physics-informed transformations designed to emphasize energy transport, use these transformations to establish new error metrics, and demonstrate that they yield smaller errors within reduced principal-component spaces compared to conventional transformations.. Authors: Cho, Min Sang [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000199861422); Grabowski, Paul E. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000289310544); Thopalli, Kowshik [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]; Jayram, Thathachar S. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]; Barrow, Michael J. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Stanford Univ., CA (United States)] (ORCID:0000000290000543). DOE Contract: AC52-07NA27344. Subjects: High-energy-density plasmas; Physics of computation; Plasma fusion; Plasma transport