Beryllium-ablator DT implosion performance at high case-to-capsule ratio on the National Ignition Facility*

Using beryllium as an ablator material has several potential advantages for inertial fusion because of its low opacity and thus higher ablation rate. This could enable novel designs taking advantage of the reduced ablation-front growth rate or operating at lower radiation temperature. We report on a series of DT layered experiments using subscale beryllium implosions at high case-to-capsule ratio to isolate the implosion physics from hohlraum uncertainties. We find that the DT performance degrades substantially relative to 1-D clean predictions as the velocity increases by increased mass ablation. The performance trends are investigated with mix models, especially between the fuel and ablator.