Viscous properties of Dusty Plasma Liquid

Dusty plasma liquid represents a multiphase medium with screened Coulomb interaction between solid gains. Laminar flow of dusty plasma liquid caused by laser beam pressure has been earlier investigated by us. Measuring of flow velocity profile allowed estimating the internal friction due to interparticles reciprocal action. This profile, obtained experimentally, is trapeziform. However Navier-Stokes equation for approaches with cylindrical symmetry requires essentially different profiles. The distinctions present in central region of flow and near its edges as well. In the central region the flow is piston-like. Parabolic form of velocity profile meets Navier-Stokes equation. It should be mentioned that the use of Navie-Stokes equation for analysis of flow necessitates its vindication, for the equation itself is not suitable for parting momentum transfer by different ways and for unambiguous separating of viscosity caused by dusty component. In this paper we report about the study of momentum transfer in laminar flow of dusty plasma liquid. Criteria of applicability of Navier-Stokes equation for experimental data processing (for wide range of parameters) have been found. The size of domain with moving dust exceeds the diameter of region affected by external action. This indicates the existence of critical shear tension, bellow the value of which there is no flow. This fact is verified experimentally. since the value of laser beam power is less than 10 mW it is observed no flow in dirty plasma liquid under conditions used. The facts mentioned above tell us about non-Newtonian character of dusty plasma medium. Moreover, dusty plasma seems to be the Bingham body. (Author)