3D simulations of polar direct drive wetted-foam capsules*

We investigate the feasibility to achieve high nuclear yields using a liquid DT-wetted layer capsule directly driven by the National Ignition Facility’s (NIF’s) current laser capabilities. The capsule is composed of a thin plastic shell used to enclose a thick annular 3D-printed matrix layer that contains the liquid DT fuel. Comparisons across several simulation codes indicate that a high level of laser absorption can occur that drives a central gas pocket convergence of 15 enabling higher levels of gain and the potential to robustly ignite (using the current laser energy available at NIF). High laser absorption is consistent with previous polar direct drive (PDD) MJ-class NIF experiments where >95% capsule absorption of the laser drive energy was achieved using a 5 mm diameter plastic capsule. The results of simulations using the HYDRA radiation-hydrodynamics code will be shown to elucidate the laser driven 3D asymmetries in the implosion of these capsules. These asymmetries arise both in polar angle (caused by the variation in laser polar angles) and in azimuthal angle (owing to the differences in laser azimuthal incidence angles) dominated by an M4 perturbation near the pole and an M8 perturbation near the equator.  Fabrication efforts using 3D printing techniques are currently underway to construct the hybrid capsule for initial NIF experiments later this year. An overview of these multi-Laboratory efforts will be presented.

R. E. Olson et al., Phys. Plasmas 28, 122704 (2021).

M. J. Schmitt, et al., https://meetings.aps.org/Meeting/DPP22/Session/JO04.13.