Trapped-electron effects on time-independent negative-bias states of a collisionless single-emitter plasma device: Theory and simulation

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859943· OSTI ID:6397535

Crystal, T L; Gray, P C; Lawson, W S; Birdsall, C K; Kuhn, S ^[1]

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

Time-average values from particle simulations of a collisionless, single-emitter plasma device modeling single-ended {ital Q} machines or thermionic converters with a negatively biased collector are presented. These results quantitatively confirm the predictions of collisionless, kinetic plane-diode theory for spatial potential profiles that decrease monotonically. However, simulations of negative-bias potential profiles with a single internal maximum differ significantly from previous theoretical predictions which assumed electron phase space to have either (i) no trapped electrons or (ii) trapped electrons isothermal with the passing electrons. A more general class of trapped-electron model distributions is introduced from which new equilibrium potential values can be recovered that closely match the simulations. These simulations clearly demonstrate the sensitive role that trapped electrons play in shaping the potential profiles of the equilibrium (or slowly evolving) states of the simulated systems. The trapped-electron distributions in these simulations are themselves shown to be controlled critically by fluctuations whose levels are varied by the choice of particle injection scheme. These effects, although found and discussed here in the context of a particular model, are believed to be important in many bounded plasma systems where electrons can be trapped in potential wells.

• DOE Contract Number: FG03-86ER53220
• OSTI ID: 6397535
• Journal Information: Physics of Fluids B; (USA), Vol. 3:1; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
42 ENGINEERING
COLLISIONLESS PLASMA
SIMULATION
ELECTRONIC CIRCUITS
ELECTRONS
EQUILIBRIUM
NEGATIVE ENERGY STATES
ONE-DIMENSIONAL CALCULATIONS
THERMIONIC CONVERTERS
TRAPPING
DIRECT ENERGY CONVERTERS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
LEPTONS
PLASMA
640410* - Fluid Physics- General Fluid Dynamics
426000 - Engineering- Components
Electron Devices & Circuits- (1990-)