A unified concept of effective one component plasma for hot dense plasmas

TL;DR

This paper introduces a unified effective one component plasma (eOCP) model for hot dense plasmas, validated through molecular dynamics simulations, which accurately captures structural, dynamical, and thermodynamic properties.

Contribution

It develops a unified eOCP framework that combines short-range structure and screening effects, improving modeling of hot dense plasmas over existing separate models.

Findings

The eOCP accurately reproduces plasma structure and relaxation timescales.

The model aligns with experimental observations in x-ray Thomson scattering.

It provides a reliable basis for calculating plasma properties like equation of state.

Abstract

Orbital-free molecular dynamics simulations are used to benchmark two popular models for hot dense plasmas: the one component plasma (OCP) and the Yukawa model. A unified concept emerges where an effective OCP (eOCP) is constructed from the short-range structure of the plasma. An unambiguous ionization and the screening length can be defined and used for a Yukawa system, which reproduces the long range structure with finite compressibility. Similarly, the dispersion relation of longitudinal waves is consistent with the screened model at vanishing wavenumber but merges with the OCP at high wavenumber. Additionally, the eOCP reproduces the overall relaxation timescales of the correlation functions associated with ionic motion. In the hot dense regime, this unified concept of eOCP can be fruitfully applied to deduce properties such as the equation of state, ionic transport coefficients, and the ion feature in x-ray Thomson scattering experiments.