Unified first-principles equations of state of deuterium-tritium mixtures in the global inertial confinement fusion region

Abstract

Accurate knowledge of the equation of state (EOS) of deuterium-tritium (DT) mixtures is critically important for inertial confinement fusion (ICF). Although the study of EOS is an old topic, there is a longstanding lack of global accurate EOS data for DT within a unified theoretical framework. DT fuel goes through very wide ranges of density and temperature from a cold condensed state to a hot dense plasma where ions are in a moderately or even strongly coupled state and electrons are in a partially or strongly degenerate state. The biggest challenge faced when using first-principles methods for obtaining accurate EOS data for DT fuel is the treatment of electron-ion interactions and the extremely high computational cost at high temperatures. In the present work, we perform extensive state-of-the-art ab initio quantum Langevin molecular dynamics simulations to obtain EOS data for DT mixtures at densities from 0.1 g/cm3 to 2000 g/cm3 and temperatures from 500 K to 2000 eV, which are relevant to ICF processes. Comparisons with average-atom molecular dynamics and orbital-free molecular dynamics simulations show that the ionic strong-coupling effect is important for determining the whole-range EOS. This work can supply accurate EOS data for DT mixtures within a unified ab initio framework, as well as providing a benchmark for various semiclassical methods.