Effects of Electric Fields on the Transport Properties of Complex Plasmas

When dust particles coexist with plasma, the resulting system is called a complex plasma (CP), and CPs exhibit electrorheological characteristics under the influence of electric fields. The effects of an externally applied electric field on the transport properties of complex plasmas in different orientations are investigated using molecular dynamics simulations. These transport properties—diffusion, shear viscosity, and thermal conductivity—are calculated based on the Green-Kubo formulas. The results show that the diffusion of particles in the parallel direction increases due to attractive interactions, while it decreases in the perpendicular direction because of repulsive interactions. Similarly, the shear viscosity initially decreases slightly for low electric field strengths but then increases sharply (by an order of magnitude) under intermediate fields and remains quite stable under high field strengths. The thermal conductivity increases in all three directions of the electric field, though the rate of increase depends on the axial direction of the simulation box and the field orientation. The investigations demonstrate that the current equilibrium molecular dynamics scheme is highly efficient for non-ideal gas-like, liquid-like, and solid-like states of strongly coupled CPs. These findings are significant for understanding diffusivity, phase transitions, and rheological behaviors in systems of charged particles and colloidal suspensions. CPs under external electric fields are potential candidates for smart fluids, with possible applications ranging from shock absorbers in automobiles to soft robotic components and artificial heart valves.