Molecular dynamics investigation of soliton propagation in a two‐dimensional Yukawa liquid

Abstract

We investigate via Molecular Dynamics simulations the propagation of solitons in a twodimensional many-body system characterized by Yukawa interaction potential. The solitons are created in an equilibrated system by the application of electric field pulses. Such pulses generate pairs of solitons, which are characterized by a positive and negative density peak, respectively, and which propagate into opposite directions. At small perturbation, the features propagate with the longitudinal sound speed, form which an increasing deviation is found at higher density perturbations. An external magnetic field is found to block the propagation of the solitons, which can, however, be released upon the termination of the magnetic field and can propagate further into directions that depend on the time of trapping and the magnetic field strength.

Numerical validation of Yukawa fluid excitations within the quasilocalized charge approximation (QLCA) theory

“…The formation of a sharp leading edge and an elongated trailing edge is an occurrence in positive density peaks, whereas negative density peaks tend to undergo the opposite transformation. [ 17 ] These findings closely match the negative peak density patterns seen in the QLCA model, confirming that the QLCA model is accurate in predicting nonlinear collective excitations. The QLCA approach qualitatively agrees with the MD simulation results, validating its usefulness as a theoretical framework for studying these structures.…”

“…It is shown that the intensity of rarefactive soliton increases with increasing the value of $$$ \kappa $$$. These predictions show a close agreement with the simulation, [ 17 ] where the intensity of negative peaked density increases with $$$ \kappa $$$ or amplitude of the perturbation.…”

“…The possibility of both compressional and rarefactive solitons has also been discussed within the QLCA model, predicting that the intensity of the negatively peaked density increases with $$$ \kappa $$$ or the amplitude of the perturbation. These predictions are also confirmed with MD simulations on highly screened dust nonlinear structures, [ 17 ] conducted with a constant value of $$$ \Gamma $$$. The QLCA approach qualitatively agrees with the MD simulation results, validating its usefulness as a theoretical framework for studying these structures.…”

“…Among these models are a simple fluid [ 13 ] and the generalized hydrodynamical (GH) model, [ 10,14 ] which describe the weak and strong coupling limits of dust media, respectively. However, a more advanced theoretical framework [ 12 ] or first principles molecular dynamics (MD) simulation [ 15–17 ] is required to adequately describe the nonlinear excitations in a strongly coupled quasi‐localized limit of dusty media. Unlike solids or gases, quasi‐localized states lack certain simplifying features, such as the ability to assume a fixed shape or volume, and they combine large displacements with strong interactions, further complicating the theoretical underpinnings of their behavior.…”

Experiment and model for a Stokes layer in a strongly coupled dusty plasma

“…Besides providing an intuitive way of visualizing a Stokes layer, these diagrams also allow an easy identification of features such as the depth of penetration and the wavelength. We are motivated to use space-time diagrams because they are familiar in the dusty plasma literature, not for Stokes layers, but for other purposes [40,67,68,[81][82][83][84][85][86][87][88][89], including the characterization of density waves [90][91][92][93][94][95]. Some of these authors have used the terms periodograms or periodgrams for such plots.…”