Structural order and disorder in strongly coupled Yukawa liquids

Abstract

The order-disorder structures (OD-structures) and the corresponding Yukawa thermal conductivity along with energies of three-dimensional strongly coupled Yukawa liquids (SCYLs) have been investigated by employing a modified homogenous nonequilibrium molecular dynamics (HNEMD) technique. The obtained results for Yukawa thermal conductivity with suitable normalization are measured over a wide range of various plasma states of the plasma coupling (Γ) and screening length (κ) in a canonical ensemble (NVT). The new HNEMD simulations indicate that the Yukawa system remains in disorder or weak to intermediate order states at the minimum value of thermal conductivity. In our new simulations, the system size does not affect the behavior of the lattice correlation [Ψ(τ)] while the long range order shifts toward high Γ with an increment of κ. The calculations for OD-structures show that the plasma system remains in the nonideal strongly coupled range during the complete simulation time. Investigations show that the Yukawa kinetic energy is not affected by the system size and it is also independent of time steps (Δτ) and κ but it depends on the system temperature (=1/Γ). The calculations show that the potential energy has its maximum when the Yukawa system remains in the moderate to higher degree of order (strongly coupled regime) and has a minimum value when system is in the disorder state (nonideal gas range). It is shown that an alternative method is employed to compute the long range order in dusty plasma systems, for making the HNEMD simulations very efficient and can be used to predict the OD-structures in 3D nonideal SCYLs.