Evidence for stratification of deuterium-tritium fuel in inertial confinement fusion implosions

Abstract

Measurements of the $D(d, p)T$ $(dd)$ and $T(t, 2n)^{4}\text{He}$ $(tt)$ reaction yields have been compared with those of the $D(t, n)^{4}\text{He}$ $(dt)$ reaction yield, using deuterium-tritium gas-filled inertial confinement fusion capsule implosions. In these experiments, carried out on the OMEGA laser, absolute spectral measurements of $dd$ protons and $tt$ neutrons were obtained. From these measurements, it was concluded that the $dd$ yield is anomalously low and the $tt$ yield is anomalously high relative to the $dt$ yield, an observation that we conjecture to be caused by a stratification of the fuel in the implosion core. This effect may be present in ignition experiments planned on the National Ignition Facility.