Testing thermal conductivity models with equilibrium molecular dynamics simulations of the one-component plasma

Abstract

Equilibrium molecular dynamics simulations are used to calculate the thermal conductivity of the one component plasma (OCP) via the Green-Kubo formalism over a broad range of Coulomb coupling strength, 0.1 ≤ Γ ≤ 180. These simulations address previous discrepancies between computations using equilibrium versus nonequilibrium methods. Analysis of heat flux autocorrelation functions show that very long (6 × 10 5 ω −1 p ) time series are needed to reduce the noise level to allow 2% accuracy. The new simulations provide the first accurate data for Γ 1. This enables a test of the traditional Landau-Spitzer theory, which is found to agree with the simulations for Γ 0.3. It also enables tests of theories to address moderate and strong Coulomb coupling. Two are found to provide accurate extensions to the moderate coupling regime of Γ 10, but none are accurate in the Γ 10 regime where potential energy transport and coupling between mass flow and stress dominate thermal conduction.

Vibrational model of thermal conduction for fluids with soft interactions

“…Transport properties of the OCP and related system are very well investigated in classical MD simulations. Extensive data on the self-diffusion [41][42][43][44], shear viscosity [17,[45][46][47][48], and thermal conductivity [45,[49][50][51] have been published and discussed in the literature. Substantial progress in ab initio studies of related systems has been also achieved [52,53].…”

Bridge functions of classical one-component plasmas

“…Given also its simplicity and its low computational cost, we expect this approach to replace all known integral equation theory approaches that have been devised for Coulomb and Yukawa liquids. Taking into account the availability of accurate equations of state from computer simulations, this conclusion mainly concerns the calculation of static properties that, however, also constitute external input for the theoretical description of dynamic and transport properties, see for instance the quasi-localized charge approximation for collective modes [113,114], the viscoelastic dynamic density functional theory for wave dispersion [115,116], the nonperturbative moment approach of dynamic density-density correlations [117,118], the mode coupling theory of the glass transition [107,119,120] and the static local field corrected kinetic model of the thermal conductivity [121,122].…”

Classical bridge functions in classical and quantum plasma liquids

“…The OCP and the YOCP liquid states, although squeezed in a rather small portion of the phase diagram between the gas and the crystal states, have proven to be the most theoretically elusive due to their lack of small parameters that forbid perturbative expansions viable for weak interactions or small vibrations [11,12]. A particular attention has been paid to their structural and thermodynamic properties, since these also constitute input for advanced theoretical descriptions of collective modes [13][14][15], dynamical properties [16] and transport coefficients [17].…”