The generation of higher harmonics of the magnetoplasmon frequency which has recently been reported in strongly coupled two-dimensional Yukawa systems is investigated in detail and, in addition, extended to two-dimensional Coulomb systems. We observe higher harmonics over a much larger frequency range than before and compare the theoretical prediction with the simulations. The influence of the coupling, structure, and thermal energy on the excitation of these modes is examined in detail. We also report on the effect of friction on the mode spectra to make predictions about the experimental observability of this new effect.
In a non-ideal classical Coulomb one-component plasma (OCP) all thermodynamic properties are known to depend only on a single parameter -- the coupling parameter $Γ$. In contrast, if the pair interaction is screened by background charges (Yukawa OCP) the thermodynamic state depends, in addition, on the range of the interaction via the screening parameter $κ$. How to determine in this case an effective coupling parameter has been a matter of intensive debate. Here we propose a consistent approach for defining and measuring the coupling strength in Coulomb and Yukawa OCPs based on a fundamental …
Isomorph theory is employed in order to establish a mapping between the bridge function of Coulomb and Yukawa one-component plasmas. Within an exact invariance ansatz for the bridge functions and by capitalizing on the availability of simulation-extracted Coulomb bridge functions, an analytical Yukawa bridge function is derived which is inserted into the integral theory framework. In spite of its simplicity and computational speed, the proposed integral approach exhibits an excellent agreement with computer simulations of dense Yukawa liquids without invoking adjustable parameters.
Very simple explicit analytical expressions, which are able to describe the dispersion relations of collective modes in strongly coupled plasma fluids, are summarized. The accuracy of these expressions is demonstrated using the comparison with available results from benchmark numerical simulations.
Fluid Modes of a Spherically Confined Yukawa Plasma
通过求解线性化的冷流体方程，研究了三维汤川等离子体在各向同性简谐约束下的简正模。本征模被发现解析和表达的超几何函数。发现模式频率仅依赖于无量纲等离子体参数$ξ=κR$，其中$R$为等离子体半径，$κ$为屏蔽长度的倒数.本征频率随$ξ$单调增加，并在极限$ξ\to\infty$处饱和。与库仑极限下的结果进行了比较。H. E. Dubin，Phys. Rev. Lett. \textbf{66}，2076（1991）]中，我们发现了一类新的模式，其特征在于数量$n$，它决定了径向节点的数量在扰动势。这些模式起源于库仑系统的简并体模。极限情况下的本征频率的解析公式推导。
Observations made in dusty plasma experiments suggest that an ensemble of electrically charged solid particles, confined in an elongated trap, develops structural inhomogeneities. With narrowing the trap the particles tend to form layers oriented parallel with the trap walls. In this work we present theoretical and numerical results on the structure of three-dimensional many-particle systems with screened Coulomb (Yukawa) inter-particle interaction in the strongly coupled liquid phase, confined in one-dimensional harmonic trap, forming quasi-2D configurations. Particle density profiles are cal…
We present a parametrization of the pair correlation function and the static structure factor of the Coulomb one component plasma (OCP) from the weakly coupled regime to the strongly coupled regime. Recent experiments strongly suggest that the OCP model can play the role of a reference system for warm dense matter. It can provide the ionic static structure factor that is necessary to interpret the x-ray Thomson scattering measurements, for instance. We illustrate this with the interpretation of a x-ray diffraction spectrum recently measured, using a Bayesian method that requires many evaluatio…
A vibrational model of heat conduction in liquids with soft pairwise interactions is applied to estimate the thermal conductivity coefficient of strongly coupled Yukawa fluids. A reasonable agreement with the available data from numerical simulations is observed. The results can be useful in the context of strongly coupled plasma and complex (dusty) plasma fluids, when Yukawa (or screened Coulomb) interaction potential is applicable.
In this work, we present a phenomenological study of the complete analytical solution to the bound eigenstates and eigenvalues of the Yukawa potential obtained previously using the hidden supersymmetry of the system and a systematic expansion of the Yukawa potential in terms of $δ=a_{0}/D$, where $a_{0}$ is the Bohr radius and $D$ is the screening length. The eigenvalues, $ε_{nl}(δ)$, are given in the form of Taylor series in $δ$ which can be systematically calculated to the desired order $δ^{k}$. Coulomb $l$-degeneracy is broken by the screening effects and, for a given $n$, $ε_{nl}(δ)$ is la…
Thermodynamics of two-dimensional Yukawa (screened Coulomb or Debye-Hückel) systems is studied systematically using molecular dynamics (MD) simulations. Simulations cover very broad parameter range spanning from weakly coupled gaseous states to strongly coupled fluid and crystalline states. Important thermodynamic quantities such as internal energy and pressure are obtained and accurate physically motivated fits are proposed. This allows us to put forward simple practical expressions to describe thermodynamic properties of two-dimensional Yukawa systems. For crystals, in addition to numerical …
We report accurate molecular dynamics calculations of the shear stress relaxation in a two-dimensional strongly coupled Yukawa liquid over a wide range of the Coulomb coupling strength $Γ$ and the Debye screening parameter $κ$. Our data on the relaxation times of the ideal- , excess- and total shear stress auto-correlation ($τ^{id}_M, τ^{ex}_M, τ_M$ respectively) along with the lifetime of local atomic connectivity $τ_{LC}$ leads us to the following important observation. Below a certain crossover $Γ_c(κ)$, $τ_{LC} \rightarrow τ^{ex}_M$, directly implying that here $τ_{LC}$ is the microscopic …
Sound velocities in classical single-component fluids with Yukawa (screened Coulomb) interactions are systematically evaluated and analyzed in one-, two-, and three spatial dimensions (${\mathcal D}=1,2,3$). In the strongly coupled regime the convenient sound velocity scale is given by $\sqrt{Q^2/Δm}$, where $Q$ is the particle charge, $m$ is the particle mass, $n$ is the particle density, and $Δ=n^{-1/{\mathcal D}}$ is the unified interparticle distance. The sound velocity can be expressed as a product of this scaling factor and a dimension-dependent function of the screening parameter, $κ=Δ/…
