Fluidlike studies of the sheath and presheath regions of a plasma
- Wisconsin Univ., Madison, WI (USA). Dept. of Nuclear Engineering and Engineering Physics
We investigate the problem of a collisional plasma flowing into a perfectly absorbing wall including the parallel viscosity and heat flux effects. Both the collisional presheath and the collisionless sheath regions are modelled by fluid-like moment equations that are derived from kinetic theory. Previous work has been based primarily on a collisionless kinetic theory or collisional Braginskii equations which have singularities at the sheath edge. The electron distribution function is obtained here from the solution of a Pastukhov type problem instead of a simple Boltzmann relation. For the ions a kinetic theory is required to determine the ion viscous stress tensor and heat flux because the collisional mean free path is comparable to the characteristic gradient scale length in the presheath region. A boundary layer analysis is applied for determining the distribution function of the ions in the velocity space region corresponding to no net return flux from the wall. This analysis provides a continuous solution over the entire region of interest. The viscous force deduced from this distribution function, which is a cutoff Maxwellian relaxed by collisions, is comparable to the electric field force everywhere and removes the singularity between the presheath and the sheath regions in the ion momentum equation. The total heat flux obtained using the same method as for the viscous force removes the singularity in the ion energy conservation equation. Four different numerical calculation cases are presented in this thesis.
- Research Organization:
- Wisconsin Univ., Madison, WI (USA). Center for Plasma Theory and Computation
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- FG02-86ER53218
- OSTI ID:
- 5618508
- Report Number(s):
- UW-CPTC-91-4; ON: DE91013343
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
PLASMA SHEATH
FLOW MODELS
COLLISIONAL PLASMA
DISTRIBUTION FUNCTIONS
FOKKER-PLANCK EQUATION
HEAT FLUX
VISCOSITY
DIFFERENTIAL EQUATIONS
EQUATIONS
FUNCTIONS
MATHEMATICAL MODELS
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
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