First-Principles Simulations of Dense Hydrogen: Equation of State and Radiative Transport Properties

Hydrogen plays a pivotal role in inertial confinement fusion (ICF) experiments and serves as a benchmark system for validating high-energy-density (HED) plasma models. In this work, we perform large-scale density functional theory molecular dynamics (DFT-MD) simulations to compute the equation of state (EOS) and transport properties of hydrogen across a broad parameter space relevant to ICF, spanning temperatures from 1,000 to 1,000,000 K and densities up to 70 g/cm³. [1] We extract electrical and thermal conductivities using the Kubo-Greenwood formalism[2], report Seebeck coefficients, and opacities, which are crucial for modeling radiation transport in fusion plasmas. Our results are directly relevant to ongoing efforts in improving radiation-hydrodynamic simulations and interpreting data from shock and ramp compression experiments [3]. In particular, we discuss deviations from analytic models, including Lee-More and Spitzer-type approaches [4], and the impact of electron degeneracy and strong coupling in the warm dense regime. This work advances the theoretical foundation for predictive modeling of HED systems and contributes to the development of more accurate opacity tables for fusion applications.

[1] D. I. Mihaylov, V. V. Karasiev, S. X. Hu, J. R. Rygg, V. N. Goncharov, and G. W. Collins; Phys. Rev. B 104, 144104 (2001)

[2] Bastian Holst, Ronald Redmer, and Michael P. Desjarlais; Phys. Rev. B 77, 184201 (2008)

[3] M. D. Knudson et al.; Science 348, 1455-1460 (2015)

[4] Uwe Kleinschmidt, Ronald Redmer; Matter Radiat. Extremes 1 July 2025; 10 (4): 047602