Exploration of polar direct drive wetted foam concepts for neutron sources on the National Ignition Facility laser

Abstract

A multi-laboratory collaborative effort is currently exploring the feasibility of laser direct drive liquid deuterium–tritium (DT) wetted foam inertial confinement fusion concepts being considered for novel neutron sources on the National Ignition Facility (NIF) laser. In contrast to the laser indirect drive approach that recently demonstrated ignition in the laboratory, these concepts also offer the potential of multi-MJ yields but with less damaging laser drives, improved robustness to target and drive imperfections, and enhanced facility fielding flexibility and orders-of-magnitude less target debris: favorable aspects for neutron exposure environments and inertial fusion energy concepts, alike. We present the current status of the experimental platform and radiation-hydrodynamics modeling development efforts to better understand the potential risks and benefits associated with these designs for the envisioned implementation on the NIF laser encompassing (i) novel two-photon-polymerization additively manufactured capsules, (ii) cryogenic target cooling through a large conductive fill tube, (iii) polar direct drive, and (iv) direct laser ablation of the liquid DT wetted foam layer.