Collective modes in two-dimensional one-component-plasma with logarithmic interaction

TL;DR

This paper investigates the collective oscillation modes of a two-dimensional one-component plasma with logarithmic interactions, revealing that dispersion relations are largely unaffected by coupling strength and can be accurately described by simple analytical expressions.

Contribution

The study combines quasi-crystalline approximation with molecular dynamics simulations to derive simple, accurate dispersion relations for the plasma's collective modes across all wavelengths.

Findings

Dispersion curves are nearly independent of coupling strength in the strongly coupled regime.

Simple analytical expressions for dispersion relations match well with exact QCA results.

Comparison with fluid analysis highlights differences and validates the approach.

Abstract

The collective modes of a familiar two-dimensional one-component-plasma with the repulsive logarithmic interaction between the particles are analysed using the quasi-crystalline approximation (QCA) combined with the molecular dynamic simulation of the equilibrium structural properties. It is found that the dispersion curves in the strongly coupled regime are virtually independent of the coupling strength. Arguments based on the excluded volume consideration for the radial distribution function allow us to derive very simple expressions for the dispersion relations, which show excellent agreement with the exact QCA dispersion over the entire domain of wavelengths. Comparison with the results of the conventional fluid analysis is performed and the difference is explained.