Comparing simulation and experiment for fuel-ablator mixing in HDC implosions at the NIF*

A variety of features in high-density-carbon (HDC) ablators, such as pits, voids, high-Z inclusions, and the intrinsic microstructure of the HDC itself, are believed to lead to mixing of fuel and ablator in inertial confinement fusion (ICF) implosions. While ICF implosions with HDC have achieved ignition and delivered record fusion yields, significant uncertainty remains around whether performance in HDC implosions will be limited by pollution of larger-radius regions of the dense fuel with ablator, due to uncertainties around mix sources and modeling them. A series of experiments at the National Ignition Facility (NIF) has measured in-flight mixing of fuel and ablator for a variety of HDC implosions using high-resolution radiography. Here we present comparisons of high-resolution simulations, including modeling of HDC microstructure or defects, with these experiments. We assess resulting constraints on the modeling of perturbation sources in HDC implosions.