Atomic mix in directly driven inertial confinement implosions

Abstract

Directly driven implosions on the Omega laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have measured the presence of atomic mix using D+T neutron yield rates from plastic capsules with and without deuterated layers, and a nearly pure tritium fuel containing 0.7% deuterium. In 15, 19, and 24 μm thick plastic shells, D+T neutron yields increased by factors of 86, 112, and 24 when the 1.2 μm thick inner layer was deuterated. Based on adjusting a fully atomic mix modvfel to fit yield degradation in the un-deuterated capsule and applying it to the capsule with the deuterated layer, atomic mixing accounts for 40–75% of the yield degradation due to mix. For the first time, the time dependence of mixed mass was measured by the ratio of the yield rates from both types of capsules. As expected, the amount of mix grows throughout the D+T burn.