Plasma boundary sheath in the afterglow of a pulsed inductively coupled RF plasma

M. Osiac, T. Schwarz-Selinger, Deborah O'Connell, B. Heil, Petrovic Z. Lj, M.M. Turner, Timo Gans, U. Czarnetzki

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The sheath dynamics in the afterglow of a pulsed inductively coupled plasma, operated in hydrogen, is investigated. It is found that the sheath potential does not fully collapse in the early post-discharge. Time resolved measurements of the positive ion flux in a hydrogen plasma, using a mass resolved ion energy analyser, reveal that a constant 2 eV mean ion energy persists for several hundred micro-seconds in the afterglow. The presence of a finite sheath potential is explained by super-elastic collisions between vibrationally excited hydrogen molecules and electrons in the afterglow, leading to an electron temperature of about 0.5 eV. Plasma density decay times measured using both the mass resolved energy analyser and a Langmuir probe are in good agreement. Vibrational temperatures measured using optical emission spectroscopy support the theory of electron heating through super-elastic collisions with vibrationally excited hydrogen molecules. Measurements are also supported by numerical simulations and modelling results.
Original languageEnglish
Article number019
Pages (from-to)355-363
Number of pages9
JournalPlasma Sources Science and Technology
Volume16 (2)
Issue number2
DOIs
Publication statusPublished - 01 May 2007

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Condensed Matter Physics

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