Collector and source sheaths of a finite ion temperature plasma

Journal Article · Tue May 01 04:00:00 EDT 1990 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859279· OSTI ID:7000027

Schwager, L A; Birdsall, C K ^[1]

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1. Electronics Research Laboratory, University of California, Berkeley, California 94720 (USA)

The region between a Maxwellian plasma source and an absorbing surface is described theoretically with a static, kinetic plasma--sheath model and modeled numerically with a dynamic, electrostatic particle simulation. In the kinetic theory, Poisson's equation and Vlasov equations govern the non-Maxwellian velocity distribution of the ions and electrons. The results in this paper for collector potential and plasma transport agree with the bounded model of Emmert {ital et} {ital al}. (Phys. Fluids {bold 23}, 803 (1980)). However, this approach differs from those using traditional Bohm sheath analysis by {plus minus}0.25 (in units of electron temperature) for potential drop through the collector sheath of a hydrogen plasma. In both the theory and simulation, the plasma source injects equal fluxes of ions and electrons with half-Maxwellian velocities and various mass and temperature ratios and is assumed to have a zero electric field. The potential change within a spatially distributed, full Maxwellian source region is represented with the source sheath potential drop that depends primarily on temperature ratio. This source sheath evolves over a few Debye lengths from the source to neutralize the injected plasma. The plasma flows to an electrically floating collector where the more familiar electron-repelling collector sheath appears. The collector potential {psi}{sub {ital C}} and source sheath potential drop {psi}{sub {ital P}} (in units of electron temperature) are evaluated as a function of mass and temperature ratio. The velocity moments of density, drift velocity, temperature, kinetic energy flux, and heat flux are also derived as a function of {psi}{sub {ital C}} and {psi}{sub {ital P}}. Comparisons with electrostatic particle simulations are shown for the ion/electron mass ratios of 40 and 100 and temperature ratios of 0.1, 1, and 10.

• DOE Contract Number: FG03-86ER53220
• OSTI ID: 7000027
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:5; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103* -- Fusion Energy-- Plasma Research-- Kinetics
BOLTZMANN STATISTICS
BOLTZMANN-VLASOV EQUATION
BOUNDARY CONDITIONS
CHARGED PARTICLES
COLLISIONLESS PLASMA
DEBYE LENGTH
DIFFERENTIAL EQUATIONS
DIMENSIONS
DISTRIBUTION
ELECTRONS
ELECTROSTATICS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
ION DRIFT
ION TEMPERATURE
IONS
KINETIC EQUATIONS
LENGTH
LEPTONS
NUMERICAL SOLUTION
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
PLASMA SHEATH
PLASMA SIMULATION
POISSON EQUATION
SIMULATION
VELOCITY