Long-duration direct drive hydrodynamics experiments on the National Ignition Facility: Platform development and numerical modeling with CHIC

摘要

We report on a novel planar direct-drive platform for hydrodynamics experiments on the National Ignition Facility (NIF). Its commissioning has been performed as part of the NIF Discovery Science Program. This platform enables the use of a 30ns drive at an average intensity of 200 TW/cm(2), creating a planar shock and ablation front over a 2mm radius. To benchmark the performance of this design, the planarity of both the shock and ablation fronts has been measured between 26ns and 28ns after the start of the laser drive in a 3mm-thick CH foil. The platform was then used to measure late-time Rayleigh-Taylor instability (RTI) growth at the ablation front for a 2D-rippled 300 mu m-thick CH foil. Simultaneously, a numerical platform has been developed with the CHIC radiation hydrodynamics code at the CELIA laboratory. The CHIC numerical platform allows, for the first time, a complete simulation of the experiments over 30ns to be performed. Large-scale simulations recover the trajectory and the 2D RTI growth measurements. They are further compared with half-mode simulations performed with identical parameters. We show that both numerical techniques fit with analytical modeling of RTI growth and discuss plans for future campaigns. Published under license by AIP Publishing.