Crystalline order and disorder in dusty plasmas investigated by nonequilibrium molecular dynamics simulations

The particle structure of a complex system has been explored through a unique Evans' s homogenous nonequilibrium molecular dynamics(HNEMD) simulation technique. The crystalline order–disorder structures(OD-structures) and the corresponding energies of three-dimensional(3 D) nonideal complex systems(NICSs) have been measured over a wide range of plasma states(■, κ) for a body-centered cubic(BCC) structure. The projected technique provides accurate ODstructures with fast convergence and applicable to very small size effect for different temperatures(≡ 1/■) and constant force field(F~*) values. The OD-structure obtained through HNEMD approach is found to be reasonable agreement and more reliable than those earlier identified by simulation approaches and experimental data of NICSs. New simulations of OD-structures show that dusty plasma remains in crystalline(strongly coupled) state at lower temperature and constant F*values, for the whole simulation runs. Our investigations show that the crystalline structure is changed and the particle structure switches from intermediate to disorder(nonideal gaseous) state with an increase of the system's temperature. It has been shown that the long range order shifts toward lower temperature with increasing κ. The presented technique exhibits that the potential energy has a maximum value when the dusty plasma remains in crystalline states(low temperatures),which confirms earlier 3 D simulation results.

Thermal Conductivity of Complex Plasmas Using Novel Evan-Gillan Approach

The thermal conductivity of complex fluid materials(dusty plasmas) has been explored through novel Evan-Gillan homogeneous non-equilibrium molecular dynamic(HNEMD) algorithm. The thermal conductivity coefficient obtained from HNEMD is dependent on various plasma parameters(Γ, κ). The proposed algorithm gives accurate results with fast convergence and small size effect over a wide range of plasma parameters. The cross microscopic heat energy current is discussed in association with variation of temperature(1/Γ) and external perturbations(P_z). The thermal conductivity obtained from HNEMD simulations is found to be very good agreement and more reliable than previously known numerical techniques of equilibrium molecular dynamic, nonequilibrium molecular dynamic simulations. Our new investigations point to an effective conclusion that the thermal conductivity of complex dusty plasmas is dependent on an extensive range of plasma coupling(Γ) and screening parameter(κ) and it varies by the alteration in these parameters.It is also shown that a different approach is used for computations of thermal conductivity in 2D complex plasmas and can be appropriate method for behaviors of complex systems.