Structure of Multicomponent Coulomb Crystals

TL;DR

This paper investigates the structure of multicomponent Coulomb crystals through molecular dynamics simulations, revealing how charge variance affects lattice order and defect formation in astrophysical plasma conditions.

Contribution

It provides the first detailed analysis of multicomponent Coulomb crystal structures near melting temperatures using realistic astrophysical compositions.

Findings

Low charge particles form interstitial defects.

Large charge variance leads to screening effects that preserve long-range order.

Low charge particles exhibit quasi-liquid behavior within the lattice.

Abstract

Coulomb plasmas crystallize in a number of physical systems, such as dusty plasmas, neutron star crusts, and white dwarf cores. The crystal structure of the one component and binary plasma has received significant attention in the literature, though the less studied multicomponent plasma may be most relevant for many physical systems which contain a large range of particle charges. We report on molecular dynamics simulations of multicomponent plasmas near the melting temperature with mixtures taken to be realistic X-ray burst ash compositions. We quantify the structure of the crystal with the bond order parameters and radial distribution function. Consistent with past work, low charge particles form interstitial defects and we argue that they are in a quasi-liquid state within the lattice. The lattice shows screening effects which preserves long range order despite the large variance in particle charges which may impact transport properties relevant to astrophysics.