Electric field reversals in dc negative glow discharges

Richard A. Gottscho, Annette Mitchell, Geoffrey R. Scheller, Yin Yee Chan, David B. Graves

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Electric field reversals play an important role in maintaining glow discharges by determining the partitioning of ion flux between cathode and anode. For years, the existence of field reversals in the negative glow has been the subject of controversy. For a range of pressures, gas compositions, and electrode spacings, we observe field reversals using laser optogalvanic (LOG) spectroscopy: The discharge current is increased by excitation of molecular ions to a state with larger mobility. The sign of the LOG signal is a direct measure of the sign of the electric field. A single-beam electron model, where it is assumed that the glow is sustained by a monoenergetic, unidirectional beam of electrons emanating from the cathode, is in good agreement with most experimental observations. The model accurately predicts the existence of field reversals and the spatial dependence of both LOG and laser-induced fluorescence signals. By including momentum and energy dispersion in the beam, the model could be further improved.

Original languageEnglish (US)
Pages (from-to)6407-6414
Number of pages8
JournalPhysical Review A
Volume40
Issue number11
DOIs
StatePublished - 1989
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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