Efficacy of an Anti-Mix Layer on Implosions of the Pushered Single Shell Platform

The Pushered Single Shell (PSS) campaign at the National Ignition Facility aims to study the efficacy of a mid -Z pusher on enhancing radiation trapping and core tamping of a burning fusion plasma. To achieve this goal, the capsule design includes a beryllium shell doped with a varying concentration of chromium, the mid-Z material, surrounding a deuterium-tritium gas. However, the presence of the chromium presents a challenge, as mixing of this material into the central hot spot tends to reduce core temperatures and yields due to increased bremsstrahlung radiation. To remedy this, an additional beryllium “anti-mix” layer is placed interior to the chromium, preventing substantial intrusion of the chromium into the core plasma.

This study aims to achieve a quantitative understanding of the anti-mix layer’s effectiveness at preventing mid -Z intrusion into the core plasma. We investigate the effectiveness of anti-mix layer on the PSS platform using the radiation-hydrodynamics code, Ares, with a Reynolds-Averaged Navier Stokes mix model. Results are validated through comparison with experimental data of the PSS platform, which included an anti-mix layer, and are then employed to estimate the effect of a reduced and/or removed anti-mix layer on shot performance.