Understanding Implosion Physics Degradations to Advance IFE-Relevant Targets

For half a century, researchers across the globe have worked to harness the potential for fusion energy to provide clean electrical power for the indefinite future. Inertial Fusion Energy (IFE) is one of two major approaches and the recent achievement of ignition and gain >1 in inertial confinement fusion (ICF) at the National Ignition Facility (NIF) has increased interest in IFE as a practical fusion energy solution. Demonstrating ignition in the laboratory was a grand scientific challenge and yet harnessing that fusion energy will be yet another grand engineering challenge on the road to fusion power production. One of the central questions facing an IFE reactor system is whether inertial fusion targets can produce significant energy gain, reliably, cheaply, and rapidly when integrated with the full reactor system. Ignition experiments have shown a significant sensitivity to enhanced radiation losses induced by impurities from the capsule shell mixing into the burning fusion fuel (mix) and implosion asymmetries because both effects compete with fusion heating. The maximum target gain in ICF depends on a competition between fusion heating and losses (from expansion, radiation, and conduction). It is therefore plausible that asymmetry in the system or a sudden increase in losses due to impurities (say from mix, introduction of wetted-foam, or high-Z cone material) could negatively affect the total gain by harming the fusion power balance. This work will assess the impacts of asymmetry and mix, establish the role of asymmetry and mix in limiting gain or preventing ignition for IFE systems, set IFE system requirements for managing these issues, and forecast impacts for several IFE concepts. This work will complement ongoing efforts in ICF while pivoting to understand how these degradations impact IFE reactor systems by advancing the understanding of hydrodynamic instabilities and asymmetries into the realm of IFE target design. Success in this research will advance our capabilities in understanding the cost and performance needed for future IFE reactors.