High-adiabat CH integrated designs for a high energy NIF upgrade

Indirect drive implosions on the NIF have repeatedly achieved fusion gain > 1 with high density carbon (HDC) capsule ablators and laser energies ≤ 2.2 MJ [1]. Plans for the NIF’s Enhanced Yield Capability (EYC) will increase the peak laser energy available from 2.2 MJ to 2.6 MJ, potentially allowing fusion yields in excess of 30 megajoules and enabling new applications in stockpile stewardship. Plastic (CH) ablators are less susceptible to instabilities seeded by capsule microstructure and more efficient in ablation than HDC ablators under typical ICF conditions, and continue to be an area of active investigation on NIF. We present integrated hohlraum simulations in the radiation-hydrodynamic code LASNEX, scaling existing high-adiabat CH designs on the present-day NIF to the 2.6 MJ/450 TW laser option which are predicted to be less susceptible to the tent perturbation which limited previous CH designs. Robustness to low-mode asymmetry and shock de-timing will be considered, as well as possible future laser configurations.

[1] A. L. Kritcher et al. "Design of first experiment to achieve fusion target gain > 1," Proc. SPIE 12939, High-Power Laser Ablation VIII, 1293905 (11 April 2024)

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.