Addendum to "Equation of state of classical Coulomb plasma mixtures".

Recently developed analytic approximation for the equation of state of fully ionized nonideal electron-ion plasma mixtures [A. Y. Potekhin, G. Chabrier, and F. J. Rogers, Phys. Rev. E 79, 016411 (2009)], which covers the transition between the weak and strong Coulomb coupling regimes and reproduces numerical results obtained in the hypernetted-chain (HNC) approximation, is modified in order to fit the small deviations from the linear mixing in the strong-coupling regime, revealed by recent Monte Carlo simulations. In addition, a mixing rule is proposed for the regime of weak coupling, which generalizes post-Debye density corrections to the case of mixtures and numerically agrees with the HNC approximation in that regime.

Improved convergence for two-component activity expansions.

It is well known that an activity expansion of the grand canonical partition function works well for attractive interactions, but poorly for repulsive interactions, such as occur between atoms and molecules. The virial expansion of the canonical partition function shows just the opposite behavior. This poses a problem for applications that involve both types of interactions, such as occur in the outer layers of low-mass stars. We show that it is possible to obtain expansions for repulsive systems that convert the poorly performing Mayer activity expansion into a series of rational polynomials that converge uniformly to the virial expansion. In the current work we limit our discussion to the second virial approximation. In contrast to the Mayer activity expansion, the activity expansion presented herein converges for both attractive and repulsive systems.

Kinetic and correlation energies and distribution functions of dense plasmas.

The mean value of the kinetic energy of a quantum plasma is investigated in Hartree-Fock and Montroll-Ward approximations using the method of thermodynamic Green's functions. Usually, one finds the kinetic energy to be larger than that of an ideal plasma due to the interaction between the particles in the system. However, also the opposite case is possible, i.e., a decrease of the kinetic energy compared to that of the ideal gas. This special correlation effect is found for temperatures of about 10(6) K and densities between 10(21) and 10(26) cm(-3). Here, the single-particle distribution function is shifted towards smaller momenta, and the binary distribution is changed.

Evidence for highly charged ion Coulomb crystallization in multicomponent strongly coupled plasmas.

Multicomponent non-neutral ion plasmas in a Penning trap consisting of Be(+) and highly charged Xe ions, having different mass-to-charge ratios than Be(+), are cooled to form strongly coupled plasmas by applying a laser-based collisional cooling scheme. The temperature of the plasma was determined from a Doppler broadened transition in Be(+). For the Xe ions, which are centrifugally separated from the Be, the Coulomb coupling parameter was estimated to be approximately 1000. Molecular dynamics simulations of the ion mixture show ordered structures, indicating crystallization of the Xe.

Collective modes in strongly correlated yukawa liquids: waves in dusty plasmas.

We determine the collective mode structure of a strongly correlated Yukawa fluid, with the purpose of analyzing wave propagation in a strongly coupled dusty plasma. We identify a longitudinal plasmon and a transverse shear mode. The dispersion is characterized by a low- k acoustic behavior, a frequency maximum well below the plasma frequency, and a high- k merging of the two modes around the Einstein frequency of localized oscillations. The damping effect of collisions between neutrals and dust grains is estimated.