Measurements of Improved Ablation Front Stabilization using a Multi-ablator Material Inertial Confinement Fusion Capsule

Experiments using a 430 TW, 970 kJ laser pulse have been conducted on the NIF (National Ignition Facility) to investigate the effect of a CH overcoat on the ablation front stability. Using the 3-rise inertial confinement fusion design, similar to recent burning plasma designs (see A. Zylstra), simulations show that the addition of a 10 μm layer significantly reduces ablation front instability growth from surface perturbations over all modes. Experimental measurements using pre-imposed surface ripples were conducted at two modes on an uncoated and CH-overcoated capsule.  Results indicate a 5× reduction in growth at mode-150 and a 20× reduction in growth at mode-90 compared uncoated HDC capsules. The results are shown to be in-line with simulation predictions.  This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.