Opposition Research: A platform for model validation of radiation flow in complex geometries

The flow of radiation through inhomogeneous media and complex geometries plays an important role in many high-energy-density (HED) systems, including astrophysical and inertial confinement fusion plasmas. Over the past decades, several HED experiments have sought to produce data critical for benchmarking numerical models of complex radiation transport and its coupling to hydrodynamic motion. However, accurate model comparisons have remained challenging due in large part to a lack of direct knowledge of the x-ray source driving the radiation transport experiment. The Opposition Research platform on the Z Facility at Sandia has enabled the study of complex radiation flow in 2D and 3D with detailed model comparisons. The platform fields a witness package on a hohlraum that directly measures the integrated x-ray drive into an opposing, complex radiation flow experiment, and which can be used to calibrate integrated radiation-hydrodynamic simulations. Experiments have produced high-quality images of radiation flow around obstructions with unprecedented detail. These data are being used to constrain high-order models of radiation transport across dynamic interfaces in integrated simulations. Initial simulations of obstructed radiation flow that have been calibrated with the witness package show remarkable agreement with data. The platform holds promise to study radiation flow in a wide variety of complex geometries and media.*



* Sandia National Laboratories is a multimission laboratory managed and operated by NTESS, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. DOE's NNSA under contract DE-NA-0003525.