Effects of Low-Mode Implosion Asymmetry, Convergence, and Hydrodynamic Scaling on Energy Coupling in Inertial Confinement Fusion

Multidimensional effects limit the laser-to-hot-spot plasma energy coupling, reducing the neutron yield and the compressed areal density of laser-direct-drive inertial confinement fusion implosions [K. M. Woo et al., Phys. Plasmas 29, 082705 (2022)]. A physics-informed 3D reconstruction technique uses a deep-learning convolutional neural network trained on 3D radiation-hydrodynamic simulations to infer the 3D hot-spot asymmetry and internal energy of the hot-spot plasma of layered deuterium–tritium cryogenic implosions on the OMEGA Laser System [K. Churnetski et al., Phys. Plasmas 32, 052711 (2025)]. The 3D reconstruction is constrained by measurements of hot-spot x-ray images recorded along multiple diagnostic lines of sight and the primary neutron yield. The effects of low-mode implosion asymmetries (due to initial target positioning, spatial variations in the DT ice thickness, laser beam mispointing, and laser beam power imbalance), convergence (associated with sub-cooling the target at the start of the implosion), and hydrodynamic scaling (realized by scaling target size while keeping the ratio of beam radius to target radius and the overlapped, on-target laser intensity constant) on the energy coupling will be presented. This material is based upon work supported by the Department of Energy [National Nuclear Security Administration] University of Rochester "National Inertial Confinement Fusion Program" under Award Number(s) DE-NA0004144.