Nuclear yield reduction in inertial confinement fusion exploding-pusher targets explained by fuel-pusher mixing through hybrid kinetic-fluid modeling

In inertial confinement fusion implosion experiments involving fast laser heating of glass capsules containing gaseous nuclear fuel, some nuclear measurements cannot be rendered by standard hydrodynamics numerical simulations. The calculated values of the nuclear yield are found to be too high by more than a decade in some cases. The first kinetic simulations of the enclosed reacting gas have bridged only half that gap. In this Rapid Communication, using a hybrid ion kinetic-fluid numerical model which takes into account the kinetic interaction between the fuel and the pusher, we reach full agreement with the experimental yield data. We thus unambiguously demonstrate that the kinetic behavior of the system, resulting in both nonthermodynamic equilibrium of the ions comprising the fuel and strong pusher-fuel mixing, is the correct interpretation of the data.

Figure 1

Space-time evolution of the density for the three species “${\mathrm{SiO}}_2$,” D, and ${}^3\mathrm{He}$ for the high-density (left column) and low-density (right column) targets.

Figure 2

Space-time evolution of the rates of the DD-$n$ and $\mathrm{D}{}^3\mathrm{He}$ nuclear reactions in the high-density target. The total yields and burn-averaged temperatures are mentioned on the respective panels.

Figure 3

Space-time evolution of the rates of the DD-$n$ and $\mathrm{D}{}^3\mathrm{He}$ nuclear reactions in the low-density target. The total yields and burn-averaged temperatures are mentioned on the respective panels.