Transport properties of partially ionized and unmagnetized plasmas
- von Karman Institute for Fluid Dynamics, Department of Aeronautics and Aerospace, 72 Chaussee de Waterloo, B-1640 Rhode-Saint-Genese (Belgium)
This work is a comprehensive and theoretical study of transport phenomena in partially ionized and unmagnetized plasmas by means of kinetic theory. The pros and cons of different models encountered in the literature are presented. A dimensional analysis of the Boltzmann equation deals with the disparity of mass between electrons and heavy particles and yields the epochal relaxation concept. First, electrons and heavy particles exhibit distinct kinetic time scales and may have different translational temperatures. The hydrodynamic velocity is assumed to be identical for both types of species. Second, at the hydrodynamic time scale the energy exchanged between electrons and heavy particles tends to equalize both temperatures. Global and species macroscopic fluid conservation equations are given. New constrained integral equations are derived from a modified Chapman-Enskog perturbative method. Adequate bracket integrals are introduced to treat thermal nonequilibrium. A symmetric mathematical formalism is preferred for physical and numerical standpoints. A Laguerre-Sonine polynomial expansion allows for systems of transport to be derived. Momentum, mass, and energy fluxes are associated to shear viscosity, diffusion coefficients, thermal diffusion coefficients, and thermal conductivities. A Goldstein expansion of the perturbation function provides explicit expressions of the thermal diffusion ratios and measurable thermal conductivities. Thermal diffusion terms already found in the Russian literature ensure the exact mass conservation. A generalized Stefan-Maxwell equation is derived following the method of Kolesnikov and Tirskiy. The bracket integral reduction in terms of transport collision integrals is presented in Appendix for the thermal nonequilibrium case. A simple Eucken correction is proposed to deal with the internal degrees of freedom of atoms and polyatomic molecules, neglecting inelastic collisions. The authors believe that the final expressions are readily usable for practical applications in fluid dynamics.
- OSTI ID:
- 20636837
- Journal Information:
- Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Vol. 70, Issue 4; Other Information: DOI: 10.1103/PhysRevE.70.046412; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-651X
- Country of Publication:
- United States
- Language:
- English
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GENERAL PHYSICS
AMBIENT TEMPERATURE
BOLTZMANN EQUATION
CHARGED-PARTICLE TRANSPORT
COLLISION INTEGRALS
CORRECTIONS
DEGREES OF FREEDOM
ELECTRONS
HYDRODYNAMICS
INTEGRAL EQUATIONS
MASS
MAXWELL EQUATIONS
MOLECULES
PERTURBATION THEORY
PLASMA
POLYNOMIALS
RELAXATION
STOCHASTIC PROCESSES
THERMAL CONDUCTIVITY
THERMAL DIFFUSION
VISCOSITY