Computational Study of Thermonuclear Burn Propagation into a Liquid DT Wetted Foam Layer

Wetted foam ICF targets employ a low-density CH foam or a 3D printed lattice to support a spherical shell of DT liquid¹. Wetted foam ICF experiments² have shown that a mixed EOS must be used to accurately simulate the implosion results. This is largely due to the fact that a DT+CH mixed EOS is less compressible than pure DT. In the present study, we explore an important additional feature of the wetted foam approach to ICF – the delay of burn propagation caused by the presence of CH in the dense DT layer at the time of ignition. Three independent radiation-hydrodynamics codes – xRAGE, HYDRA, and LILAC -- using a variety of physics and burn models have been used in the study. The overall conclusion is that, although ignition is delayed and burn propagation is slowed compared to a pure DT layer, it is feasible to obtain high fusion gain with a wetted foam target.

¹R. E. Olson et al., Phys. Plasmas 28, 122704 (2021).

²R. E. Olson et al., Phys. Rev. Lett. 117, 245001 (2016).