Jets and diffusion in ICF capsule implosions*

The diffusion of deuterium ions, transported out of the plastic shell and into the fuel region, is of major importance in recent separated-reactant capsule experiments, using shells with very thin layers (0.15-μm thick) of deuterated plastic, either adjacent to gaseous tritium fuel, or recessed into the shell at various depths [Zylstra et al., Phys. Rev. E 97, 061201(R) (2018)]. But some features of the DT yield behavior in these experiments are not explainable in 1D simulations on the basis of diffusion alone, and seem to indicate that a hydrodynamic phenomenon, such as a jet induced by the target mount, also plays a role. Initial 2D simulations of such jets show that they can increase DT yield while decreasing the TT yield, compared to simulations without a jet. There is also evidence that deuterium diffusion may be occurring in the jet.