We present the first results from an experimental campaign to measure the atomic ablator-gas mix in the deceleration phase of gas-filled capsule implosions on the National Ignition Facility. Plastic capsules containing CD layers were filled with tritium gas; as the reactants are initially separated, DT fusion yield provides a direct measure of the atomic mix of ablator into the hot spot gas. Capsules were imploded with x rays generated in hohlraums with peak radiation temperatures of $\sim 294\mathrm{eV}$. While the TT fusion reaction probes conditions in the central part (core) of the implosion hot spot, the DT reaction probes a mixed region on the outer part of the hot spot near the ablator–hot-spot interface. Experimental data were used to develop and validate the atomic-mix model used in two-dimensional simulations.

• Received 14 July 2013

DOI:https://doi.org/10.1103/PhysRevLett.112.025002