Effects of emitted electron temperature on the plasma sheath

J. P. Sheehan, I. D. Kaganovich, He Wang, D. Sydorenko, Y. Raitses, N. Hershkowitz

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

It has long been known that electron emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted electrons assumes that the plasma electrons follow the Boltzmann relation and the emitted electrons are emitted with zero energy and predicts a potential drop of 1.03Te/e across the sheath in the floating condition. By considering the modified velocity distribution function caused by plasma electrons lost to the wall and the half-Maxwellian distribution of the emitted electrons, it is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. When the plasma electron temperature equals the emitted electron temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic electron beam to the Maxwellian plasma electrons were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted electron flux is less than the beam flux.

Original languageEnglish (US)
Article number063502
JournalPhysics of Plasmas
Volume21
Issue number6
DOIs
StatePublished - Jan 1 2014
Externally publishedYes

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plasma sheaths
sheaths
electron energy
electron plasma
Maxwell-Boltzmann density function
electrons
electron flux
electron emission
floating
velocity distribution
distribution functions
electron beams
energy
fluids
predictions
cells
simulation

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Sheehan, J. P., Kaganovich, I. D., Wang, H., Sydorenko, D., Raitses, Y., & Hershkowitz, N. (2014). Effects of emitted electron temperature on the plasma sheath. Physics of Plasmas, 21(6), [063502]. https://doi.org/10.1063/1.4882260

Effects of emitted electron temperature on the plasma sheath. / Sheehan, J. P.; Kaganovich, I. D.; Wang, He; Sydorenko, D.; Raitses, Y.; Hershkowitz, N.

In: Physics of Plasmas, Vol. 21, No. 6, 063502, 01.01.2014.

Research output: Contribution to journalArticle

Sheehan, JP, Kaganovich, ID, Wang, H, Sydorenko, D, Raitses, Y & Hershkowitz, N 2014, 'Effects of emitted electron temperature on the plasma sheath', Physics of Plasmas, vol. 21, no. 6, 063502. https://doi.org/10.1063/1.4882260
Sheehan JP, Kaganovich ID, Wang H, Sydorenko D, Raitses Y, Hershkowitz N. Effects of emitted electron temperature on the plasma sheath. Physics of Plasmas. 2014 Jan 1;21(6). 063502. https://doi.org/10.1063/1.4882260
Sheehan, J. P. ; Kaganovich, I. D. ; Wang, He ; Sydorenko, D. ; Raitses, Y. ; Hershkowitz, N. / Effects of emitted electron temperature on the plasma sheath. In: Physics of Plasmas. 2014 ; Vol. 21, No. 6.
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