Pushered Single Shell (PSS) experiments with graded High-Z -- Be capsules on the National Ignition Facility*

Hydrodynamic instabilities and mix are of major interest in the field of High Energy Density physics. Graded High-Z Pushered Single Shells (PSS) capsules are predicted to achieve high neutron yields via core tamping and radiation trapping that increase confinement time and reduce bremmstrahlung losses compared to conventional inertial confinement fusion implosions. Adverse effects of core cooling by fuel gas-pusher mix are mitigated using a pure thin Be anti-mix layer. Experiments were performed recently on the National Ignition Facility (NIF) using novel capsules with graded Be/Cr metal shells that reach 50{\%} Cr concentration in the pusher and have a graded transition to pure Be ablator to mitigate hydrodynamic instabilities. Be/Cr capsules are hydrodynamic surrogates for Be/Mo capsules that are predicted to achieve fusion yields similar to ICF implosions using 6 mg/cc gas DT fuel. First Be/Cr experiments are focused on shock timing, early symmetry and implosion shape tuning. The opaque capsule implosions are characterized by neutron imaging and dedicated hard x-ray (\textless 30 keV) radiography using NIF's Advanced Radiographic Capability (ARC). The results of these first experiments and effects on mix models will be discussed.