Transition and Multiphysics in 3D ICF Capsule Implosions

ICF capsules are unique with regards to hydrodynamic instabilities: time-scales are short relative to turbulence development, so understanding the 3D transition is particularly important; 2) as the core heats, viscosity becomes important so that there is not much scale separation between the outer length scale and the viscous dissipation length scale; 3) jetting is a unique and critical phenomenon to ICF applications that arises due to Rayleigh-Taylor instability growth in a thin shell. Experiments at NIF create a new urgency for assessing the new computational paradigms and the verification and validation of their 3D modeling aspects in the research codes. We build on prior ICF simulations work, using a Navier-Stokes based plasma viscosity model in conjunction with LANL’s new xRAGE HLLC hydrodynamics with directionally unsplit algorithms and low-Mach-number correction enabling higher fidelity on coarser grids [1]. We simulate an indirect-drive NIF cryogenic capsule experiment, N170601 [2] requiring multi-group radiation diffusion to transport x-ray energy from the cylindrical Hohlraum to the target capsule. The 3D simulation model involves miscible (gas / plasma Schmidt number ~ 1) material interfaces and 3T plasma physics treatments. We use relatively coarse 2D runs through onset of turbulence, followed by mapping to highly resolved 3D mesh with suitable 3D seed-perturbations. We assess ICF predictions with the new xRAGE numerical hydrodynamics. Challenges coupling 3D hydrodynamics and multiphysics are discussed in this context. [1] Grinstein and Pereira, PoF, 33, 035126, 2021. [2] Haines et al., PoP, 27, 082703, 2020.