First-Principles Equation of State of CHON for Two-Photon-Polymerization-Fabricated Inertial Confinement Fusion Targets

A wide-range (0 to 10³ g/cm³ and 0 to 10⁹ K) equation-of-state (EOS) table for a C‑H‑O‑N quaternary compound has been constructed based on first-principles calculations using a combination of Kohn–Sham molecular dynamics, orbital-free molecular dynamics, and numerical extrapolation. The EOS data are compared with predictions of simple models, including ideal gas models in the fully ionized or strongly degenerate limit, to chart their temperature–density conditions of applicability. The shock Hugoniot is predicted based on the EOS table and compared to those of C-H compounds, which shows that the maximum compression ratio of CHON resin is larger than that of CH polystyrene because of the existence of oxygen and nitrogen. Radiation-hydrodynamic simulations have been performed using the table for inertial confinement fusion targets with a CHON shell and compared with a similar design with CH. The simulations show CHON outperforms CH as ablator for laser-direct-drive target designs, which supports the use of the two-photon-polymerization–fabricated CHON foam for laser-imprint mitigation.