Studies of force field effects on thermal conductivity of complex plasmas

Abstract

The plasma thermal conductivity of three-dimensional (3D) strongly coupled Yukawa fluids (SCYFs) has been investigated under the influence of varying external force fields through the recently improved homogenous nonequilibrium molecular dynamics (MD) approach. The effects of external field strength (F*) have been calculated along with various combinations of plasma coupling (C) and screening parameter (j) on the plasma thermal conductivity of SCYFs using homogenous nonequilibrium MD (HNEMD) simulations. New investigations show that the plasma thermal conductivity of complex plasmas decreases with an increase of external force field strength and plasma coupling (C). Our calculations show that the decreasing behavior is noted for plasma thermal conductivity with increasing screening parameter and system size. The HNEMD simulation results under different force field strengths are in satisfactory agreement with previous numerical results of nonequilibrium MD and equilibrium MD simulations and with reference data points and it showed that the deviations are within less than 620% for the presented results. It has been shown that our numerical results extended the range of external force field strength up to 0.001 F* 0.1 exercised in the previous work in order to establish the size of the linear regimes and to clarify the nature of linearity of 3D SCYFs.

Thermal Conductivity of Dusty Plasmas through Molecular Dynamics Simulations

“…NEMDS is used to obtain the trajectory of dust particles' motion of a system [13] that interacts with each other through an interparticle Yukawa potential [14]. Homogeneous nonequilibrium molecular dynamic simulation (HNEMDS) approach have used for the calculation of thermal conductivity of complex (dusty) plasma liquids, which are molded, using a most common Yukawa (screened Coulomb) potential for charged particles [15] and has the following form,…”

“…We have three normalized (dimensionless) parameters to characterize the Yukawa interaction model ϕ Y r jj ðÞ : (i) the plasma Coulomb coupling parameter define as: Γ ¼ Q 2 =4πε 0 ÀÁ : 1=a ws k B T ðÞ , where a ws is Wigner Seitz radius and it is equal to (nπ) À1/2 , here n is the number of particles per unit area (N/V). The k B and T are Boltzmann constant and absolute temperature of the system, (ii) the screening strength (dimensionless inverse) κ ¼ aws = λ D , and (iii) normalized external force field strength, F * ¼ F Z ðÞ : a ws =J Q ÀÁ [15,16]. We have applied periodic boundary conditions and Gaussian thermostat in canonical ensemble (NVT) in order to constant temperature for a Yukawa system.…”

“…The further detail of these three dimensionless parameters is given in our earlier work of Refs. [15][16][17]. We started from a well-known, the Green-Kubo relations (GKR S ) for the hydrodynamic transport coefficients of uncharged particles [18].…”

“…Mechanical work is performed through the externally applied force field F e t ðÞand thus the equilibrium cannot be maintained. In the above expression, α is the Gaussian thermostat multiplier that keeps the system temperature [15][16][17][18][19][20][21][22]28] and it is given as…”

“…In Eq. (8), J Q Z t ðÞis the z-component of the current heat vector and the external force field F e t ðÞ=(F Z ) [15][16][17][18][19][20][21][22]31]. In this study we have used the same method as employed in our earlier work of 3D strongly coupled dusty plasmas [11,12].…”