Dynamic structure factor of the magnetized one-component plasma: crossover from weak to strong coupling

TL;DR

This study investigates how the dynamic structure factor of a magnetized one-component plasma transitions from weak to strong coupling using molecular dynamics simulations, revealing spectral changes and limitations of existing models.

Contribution

It provides a detailed analysis of the crossover in the dynamic structure factor from weak to strong coupling, highlighting the failure of current theories to accurately describe this transition.

Findings

Vanishing of Bernstein modes across the magnetic field

Emergence of higher harmonics of the upper hybrid mode

Spectral power redistribution and plasmon damping suppression

Abstract

Plasmas in strong magnetic fields have been mainly studied in two distinct limiting cases--that of weak and strong nonideality with very different physical properties. While the former is well described by the familiar theory of Braginskii, the latter regime is closer to the behavior of a Coulomb liquid. Here we study in detail the transition between both regimes. We focus on the evolution of the dynamic structure factor of the magnetized one-component plasma from weak to strong coupling, which is studied with first-principle molecular dynamics simulations. The simulations show the vanishing of Bernstein modes and the emergence of higher harmonics of the upper hybrid mode across the magnetic field, a redistribution of spectral power between the two main collective modes under oblique angles, and a suppression of plasmon damping along the magnetic field. Comparison with results from various models, including the random phase approximation, a Mermin-type dielectric function, and the Quasi-Localized Charge Approximation show that none of the theories is capable of reproducing the crossover that occurs when the coupling parameter is on the order of unity. The findings are relevant to the scattering spectra, stopping power, and transport coefficients of correlated magnetized plasmas.