Thermal conductivity of three-dimensional strongly coupled Yukawa liquids (dusty plasma)


A. Shahzad1 and M. He1

1State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi'an, P. R. China

Keywords: dusty plasma, Ewald sums,
property: thermal conductivity, molecular dynamics simulation
material: Yukawa liquids

There are three basic mechanism of heat transfer. The microscopic dynamical origin of heat transfer is a fundamental problem in statistical mechanics [1] with the derivation of modified equations of motion and fully homogenous systems as the ultimate goal. The subject of a complex multicomponent plasma containing grains of solid matter (dust particles) typically of a micrometer size is now attracting much attention [2].In this work, a nonequilibrium molecular dynamics simulations (NEMD) is performed to investigate the thermal conductivity in three-dimensional strongly coupled dusty plasmas for the liquids state. Yukawa systems work as a models for dusty plasma of particulates. The simulation measurements for the thermal conductivity normalized by plasma frequency (λ1) over the wide range of plasma coupling (Γ) and screening (κ) parameters are calculated and compared with the available theories and simulations. In this present simulation, periodic boundary conditions (PBC's) geometry is used with derived Ewald sums expression for the Yukawa potentials and forces. An improved formula describing the thermal conductivity of the Yukawa systems is proposed. The Ewald sums for the energy current which enter in this formula are implemented in our numerical scheme. A simple analytical temperature representation of Yukawa thermal conductivities with appropriate normalization frequencies is performed. Yukawa thermal conductivities obtained from this NEMD simulations are slightly higher than those obtained previously based on a different numerical schemes. Our simulation data indicate that the position of the minimum of thermal conductivity normalized by plasma frequency (λ1) moves towards higher Γ with increases κ as expected. It is to be noted that the thermal conductivity normalized by Einstein frequency (λ*) increases with the increasing of κ. The minimum values of λ1 decreases with increasing of κ. The numerical measurements are comparably good coincidence with results of Salin and Caillol [3],and significantly higher than Donko and Hartmann [4], and Faussurier and Murillo [5].Our simulations provide reliable measurements of λ1 in the coupling range Γ≥10 and for screening parameter κ≥1.It is expected that three-dimensional dusty plasma will exhibits this behavior.

References
  1. D. J. Evans and G. P. Morriss, Statistical Mechanics of Non-equilibrium Liquids (Academic, London, 1990).

  2. H. M. Thomas and G. E. Morfill, Nature (London) 379, 806 (1996).

  3. G. Salin and J.-M. Caillol, Phys. Rev. Lett. 88, 065002 (2002).

  4. Z. Donko and P. Hartmann, Phys. Rev. E, 69, 016405, (2004).

  5. G. Faussurier and M. S. Murillo, Phys. Rev. E 67, 046404, (2003).

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