Unified first-principles equations of state of deuterium-tritium mixtures in the global inertial confinement fusion region
Dongdong Kang, Yong Hou, Qiyu Zeng, Jiayu Dai
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.