Ablator joint hydro growth mitigation using gold coating in double-shell ICF implosions*

Volume burn double-shell implosions suffer significantly from defect hydro instability growth from the ablator shell joint as the outer ablator shell is assembled from two hemi-shells. Numerical simulations using LANL xRGAE rad-hydro code show promising results for mitigation of the ablator joint hydro growth using a thin layer of gold (~few hundred nm thick) placed at the gap between the hemi-shells to compensate for the missing mass. The gold absorbs the X-ray preheat and fills the joint gap early on during the implosion. The amount of required gold is roughly the same as the missing mass at the ablator joint. This hypothesis is being tested at the NIF facility in the upcoming experiments. We will present the results from these experiments and the rad-hydro numerical studies.