Hot-Spot Mix and Compressed Ablator \textit{$\rho $R} Measurements in Ignition-Scale Implosions

Cu and Ge dopants placed at different radial locations in the plastic ablator of indirect-drive cryogenic DT implosions are used to study the origin of hot-spot mix via He$_{\alpha }$ + satellite emission spectroscopy, and to probe the compressed ablator \textit{$\rho $R} using K-edge absorption spectroscopy. Hot-spot mix is dominated by the ablation front instability. Low neutron yields correlate with hot-spot mix mass in excess of 75 ng. Hydrodynamic simulations of the implosion are consistent with the measured compressed ablator \textit{$\rho $R} of 0.35 to 0.5 g/cm$^{2}$. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.