Developing the Hybrid-B campaign for high laser energy and power at the National Ignition Facility*

To achieve hotspot ignition, inertial confinement fusion implosions must achieve high hotspot pressures that are inertially confined by a dense shell of DT fuel. Recent experiments at the National Ignition Facility (NIF) have shown improvements in implosion performance with increases in coupled drive/shell energy, velocity, and overall scale. To better understand these experiments, a common model was used [1] to compare HDC, CH, and Be based implosions and subsequently to develop a “hybrid” design based on many of their most successful design features. The first of these Hybrid concepts (Hybrid-B) was designed to use very high laser power  and energy at the NIF with the largest capsule scale where good hotspot/drive coupling, including symmetry control, can be maintained. Operating near the current limits of the NIF further constrains the design options for maintaining implosion low mode symmetry. Therefore, the Hybrid-B experimental campaign was conducted with two hohlraum gas-fills to develop a platform enabling future experiments at the highest energies ~2.1 MJ yet attempted at the NIF.

[1] A. Kritcher, POP 25, 056309 (2018).