Motivation and expectations for 2.2 MJ 440 TW implosions at the NIF*

The NIF implosion experiment N221204 produced more than 3 MJ of fusion yield and surpassed unity target gain for the first time. Key contributors to its improved performance were using higher laser energy and a thicker capsule ablator. 1D and 2D HYDRA modeling show still further performance improvement by moving to +0.15 MJ laser energy and +10 um thicker HDC capsule, relative to N221204. This improvement is evidenced by increased EP², yield, and increased robustness to a given level of degradation. The degradations investigated include hydrodynamic instabilities, low-mode shape asymmetry, and high-Z impurity mixing into the fusing plasma. Facility upgrades have been performed to enhance laser delivery to 2.2 MJ 440 TW, with plans for additional increases in energy and power in following years. An experimental campaign has been developed for FY24 which exploits this new capability and explores the parameter space of improved, igniting plasmas. First demonstration at 2.2 MJ 440 TW is scheduled for September 2023.