High yield design options for a next-generation ICF facility

The demonstration of fusion ignition on the National Ignition Facility (NIF) lends credibility to predictions of high-yields from a next-generation laser facility. A high-yield facility would be transformative for inertial fusion energy, stockpile stewardship, and basic high energy density science. This talk discusses the potential performance levels that could be achieved with approximately 10 MJ of laser energy delivered to an indirect-drive ICF target. Two approaches are being explored for this design work: 1) scaling aspects of the current igniting diamond implosions, and 2) a broader design search with increased fuel mass for greater fusion yield. The first, more conservative, approach preserves key parameters such as capsule convergence ratio and hohlraum plasma conditions, leveraging NIF's demonstrated pathway to ignition. This design path is expected to yield 100-200 MJ of fusion energy. The second approach pursues targets with more fuel mass, aiming for yields of 500+ MJ. This path requires some departures from the current diamond-ablator designs, such as a decreased case-to-capsule ratio, decreased radiation temperature, slower implosion velocity, and longer coast time. These designs can also benefit from alternative ablators, like CH, that have better efficiency and can be driven with a lower first-shock pressure. While this path involves greater risk, it is supported by deliberate design choices and targeted studies to reduce uncertainty, including: 1) ensuring that the hot-spot contains sufficient energy and pressure at levels that have demonstrated robust ignition on NIF, 2) designing in robustness to low-mode asymmetries and residual kinetic energy, 3) showing that hydro-dynamic instabilities at the fuel-ablator interface and at the ablation front are at levels commensurate to NIF experiments, 4) allowing greater flexibility in the power-balance of the laser cones to control symmetry without the need of laser wavelength tuning, and 5) minimizing the predicted levels of laser-backscatter using tools and practices that have been validated on NIF. There are other aspects of the design where focused NIF experiments can help validate assumptions.