2019/09/30 by Luciano G. Silvestri, Luciano G Silvestri, Gabor J. Kalman +8 · 15 citations
Physics and Astronomy · #Classical mechanics #Cold Atom Physics and Bose-Einstein Condensates #Computational physics #Coulomb #Coupling (piping) #Dispersion (optics) #Dust and Plasma Wave Phenomena #Long wavelength limit #Physics #Quantum mechanics #Quantum, superfluid, helium dynamics #Range (aeronautics) #Speed of sound #Statistical physics #Yukawa potential #physics.plasm-ph
paper · pdf · doi:10.1103/physreve.100.063206
published in Physical review. E 100(6), 063206 (American Physical Society) · 33 pages, 12 figures
openalex publication_date 2019/12/17 · arxiv created 2019/12/19 · arxiv updated 2019/12/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
A many-body system of charged particles interacting via a pairwise Yukawa potential, the so-called Yukawa one-component plasma (YOCP), is a good approximation for a variety of physical systems. Such systems are completely characterized by two parameters: the screening parameter, \ensuremathκ, and the nominal coupling strength, \mathrm\ensuremathΓ. It is well known that the collective spectrum of the YOCP is governed by a longitudinal acoustic mode, both in the weakly and strongly coupled regimes. In the long-wavelength limit, the linear term in the dispersion (i.e., \ensuremathω=sk) defines the sound speed s. We study the evolution of this latter quantity from the weak- through the strong-coupling regimes by analyzing the dynamic structure function S(k,\ensuremathω) in the low-frequency domain. Depending on the values of \mathrm\ensuremathΓ and \ensuremathκ and w=s/vth (i.e., the ratio between the phase velocity of the wave and the thermal speed of the particles), we identify five domains in the (\ensuremathκ,\mathrm\ensuremathΓ) parameter space in which the physical behavior of the YOCP exhibits different features. The competing physical processes are the collective Coulomb-like versus binary-collision-dominated behavior and the individual particle motion versus quasilocalization. Our principal tool of investigation is molecular dynamics (MD) computer simulation from which we obtain S(k,\ensuremathω). Recent improvements in the simulation technique have allowed us to obtain a large body of high-quality data in the range \mathrm\ensuremathΓ=0.1\ensuremath-10\phantom\rule0.16em0ex000 and \ensuremathκ=0.5\ensuremath-5. The theoretical results based on various models are compared in order to see which one provides the most cogent physical description and the best agreement with MD data in the different domains.