Macroion effective charge in complex plasmas with regard to microion correlations

In the present paper, features of high-charged macroions screening by microions are analysed in classical asymmetrically charged complex plasmas. We consider a two-component electroneutral system of classical macroions and oppositely charged microions in a spherically symmetrical electroneutral Wigner–Seitz cell with a central macroion in its centre. The present paper is devoted to a problem of a relation between the effective macroion charge and an initial one with regard to a non-linear screening effect and microions correlations. We show how this relation changes with the number of the central macroion charge value on the rise. Characteristics of two different parts of the relation between the effective charge and the initial one are calculated.     

Anomalous Scenario for Termination of Metastable Melting in Simplified Coulomb Models in the Zero‐Temperature Limit

Two non‐standard scenarios of melting termination in deep metastable states are studied in the zero‐temperature limit on the base of two variants of modified one‐component Coulomb models. These additional scenarios supplement the previously studied standard case of “spinodal decomposition” (Iosilevskiy and Chigvintsev, arXiv:0609059) when liquid binodal of metastable freezing (liquidus) is terminated in intersection with gas‐liquid spinodal. In the first new scenario hypothetical unique crystal‐fluid global phase coexistence is realized as smooth superposition of melting and sublimation transitions (without gas‐liquid transition and corresponding critical point). The second new type of “spinodal decomposition” scenario is related to the situation when solid binodal of metastable melting (solidus) intersects spinodal of metastable isostructural crystal‐crystal phase transition. Modified one‐component Coulomb models allow one to investigate in details all features of such “spinodal decomposition” scenarios (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Hydrogen and deuterium in shock wave experiments,ab initio simulations and chemical picture modeling

We present equation of state data of shock compressed hydrogen and deuterium. These have been calculated in the physical picture by using ab initio molecular dynamics simulations based on finite temperature density functional theory as well as in the chemical picture via the Saha-D model. The results are compared in detail with data of shock wave experiments obtained for condensed and gaseous precompressed hydrogen and deuterium targets in a wide range of shock compressions from low pressures up to megabars.     

Measurement of density, temperature, and electrical conductivity of a shock-compressed nonideal nitrogen plasma in the megabar pressure range

Kinematic and thermodynamic parameters of shock-compressed liquid nitrogen are measured behind the front of a plane shock wave using plane wave and hemispherical shock wave generators. In these experiments, high values of compression parameters (shock-compressed hydrogen density? ≈ 3.25 g/cm³ and temperature T≈ 56000 K at a pressure of P ≈ 265 GPa) are attained. The density, pressure, temperature, and electrical conductivity of the nonideal plasma of shock-compressed liquid nitrogen are measured. A nearly isochoric behavior of the nitrogen shock adiabat is observed in the pressure range P = 100–300 GPa. The thermodynamics of shock-compressed nitrogen is an alyzed using the model of the equation of state in the quasi-chemical representation (SAHA code) as well as the semiempirical wide-range equation of state developed at the Institute of Experimental Physics. Experimental results are interpreted on the basis of calculations as the fixation of the boundary of transition of shock-compressed nitrogen from the polymer phase to the state of a strongly nonideal plasma at P ≈ 100 GPa, ? ≈ 3.4 g/cm³.     

Quasi-isentropic compression of dense gaseous helium at pressures up to 500 GPa

The thermodynamic parameters??pressure and density??of quasi-isentropically compressed helium have been measured in a pressure range of 100?C500 GPa. A thermodynamic model that satisfactorily describes the behavior of strongly compressed helium in a wide range of compression parameters has been proposed.     

Quasi-Isentropic Compression of a Nonideal Plasma of Deuterium and its Mixture with Helium at Pressures up to 250 GPa

Journal of Experimental and Theoretical Physics - We present data on the quasi-isentropic compressibility of a strongly coupled (nonideal) plasma of a deuterium–helium mixture in the range of...     

Compressibility of Nonideal Deuterium and Helium Plasmas up to 20 TPa

Journal of Experimental and Theoretical Physics - We present our experimental results on the compressibility of strongly coupled (nonideal) degenerate deuterium and helium plasmas...     

Self-similarity of nonlinear screening in asymmetric complex plasmas

In this paper, two-component electroneutral systems of finite-sized macroions and oppositely charged point-like microions in the average spherical electroneutral Wigner–Seitz cell with a central macroion are studied. We investigate the self-similarity of nonlinear screening of highly charged macroions by microions in a classical asymmetrically charged complex plasma. This work is devoted to the problem of the relationship between the effective (‘visible’) charge of the macroion Z^* and its initial charge Z taking into account the effect of the nonlinear screening. It is analysed how the form of the dependence Z^*(Z) changes. The self-similarity of this dependence has been demonstrated for various characteristic system temperatures, macroion concentrations, and macroion sizes.     

Phase transition in a strongly nonideal deuterium plasma generated by quasi-isentropical compression at megabar pressures

High-explosive driven generators of cylindrical and plane shock waves in D2 and H2 were used for the generation of warm and dense strongly nonideal matter with an intense interparticle interaction and Fermi statistics. Highly resolved flash x-ray diagnostics were used to measure the adiabatic plasma compressibility. The thermodynamic measurements demonstrated the 20% increase of density at megabar pressure, just in the density range, where the electrical measurements indicated a sharp--5 orders of magnitude--increase of electrical conductivity due to pressure ionization in strongly coupled plasmas.     

Dynamics of volumetrically heated matter passing through the liquid–vapor metastable states

Remaining within the pure hydrodynamic approach, we formulate a self-consistent model for simulating the dynamic behavior of matter passing through metastable states in the two-phase liquid–vapor region of the phase diagram. The model is based on the local criterion of explosive boiling, derived by applying the theory of homogeneous bubble nucleation in superheated liquids. Practical application of the proposed model is illustrated with hydrodynamic simulations of a volumetrically uniformly heated planar layer of fused silica SiO₂. Implications for experimentally measurable quantities are briefly discussed. A newly developed equation of state, based on the well known QEOS model and capable of handling homogeneous mixtures of elements, was used in the numerical simulations.