Influence of the drive design on ablation front hydrodynamic instability growth in a capsule implosion at the National Ignition Facility*

Ignition experiments are sensitive to hydrodynamic instability growth. Control of these instabilities is crucial to achieve and optimize high gain in Inertial Confinement Fusion (ICF) as they have a critical role in performance degradations. While ignition with target gain higher than unity was demonstrated at the National Ignition Facility (NIF), drive design are being developed to increase this gain to even higher number. It is then necessary to quantify the growth of the hydrodynamic instability to assess the stability of the design and thus the achievable performances. We are reporting on the results of a campaign that uses the hydro-growth radiography platform, previously developed on NIF, to measure the mode 90 and mode 150 growth rate for three ongoing NIF campaigns using High-Density Carbon ablator: a 3-shock, a shock followed by a compression wave and a high radiative temperature with thicker ablator and ice layer design. The first two will show the dependance of the growth factor on the laser drive as the target are near identical while the latter one will assess the effect of a higher radiative temperature in at a different scale. The measurements shows a highest growth factor for the 3-shock and 2-shock deisgns, consistent with the lower radiative temperature and M-band fraction compared to the third design. Results of these experiments will be presented and compared to 2D rad-hydro modeling.