Inertial Fusion Energy Target Designs to Capitalize on Next-Generation Laser Technologies

The recent demonstration of 1.3 MJ of fusion yield with laser indirect drive (LID) at the National Ignition Facility, along with progress in target performance of laser-direct-drive (LDD) inertial confinement fusion (ICF) implosions, has sparked interest in using ICF for energy production. Recent performance improvements in both LID and LDD implosions have pushed toward designs with high adiabats and high implosion velocities with a focus on effectively coupling of energy into the hot spot. This is largely because of high levels of hydrodynamic instability and the presence of laser–plasma interactions (LPI’s) that can limit laser coupling and significantly reduce the ablative drive pressure. By contrast, in the case of high-gain designs (G > 100), lower-adiabat designs with higher mass assemblies and low implosion velocities are required. Such designs are not compatible with the LPI limitations imposed by current laser technology. Development of next-generation, broadband UV laser technologies should significantly reduce the effects of deleterious LPI, significantly increasing the drive pressure while also reducing hydrodynamic instability seeding generated by imprint. It is therefore an opportune time to explore a design space relevant to IFE that will be opened up by these technologies. We present a number of target designs with wetted foam that explore this space. Additionally, a route to widening the ignition design space is investigated using “dynamic-shell” targets. *This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856 and ARPA-E BETHE Grant No. DEFOA-0002212.