Theoretical insight into Ar-O2 surface-wave microwave discharges

K. Kutasi, Vasco Guerra, S. A. Paulo

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

A zero-dimensional kinetic model has been developed to investigate the coupled electron and heavy-particle kinetics in Ar-O2 surface-wave microwave discharges generated in long cylindrical tubes, such as those launched with a surfatron or a surfaguide. The model has been validated by comparing the calculated electron temperature and species densities with experimental data available in the literature for different discharge conditions. Systematic studies have been carried out for a surface-wave discharge generated with 2.45 GHz field frequency in a 1 cm diameter quartz tube in Ar-O2 mixture at 0.5-3 Torr pressures, which are typical conditions found in different applications. The calculations have been performed for the critical electron density for surface-wave propagation, ne = 3.74 × 10 11 cm-3. It has been found that the sustaining electric field decreases with Ar percentage in the mixture, while the electron kinetic temperature exhibits a minimum at about 80%Ar. The charged and neutral species densities have been calculated for different mixture compositions, from pure O2 to pure Ar, and their creation and destruction processes have been identified. The O2 dissociation degree increases with Ar addition into O2 and dissociation degrees as high as 60% can be achieved. Furthermore, it has been demonstrated that the dissociation degree increases with the discharge tube radius, but decreases with the atomic surface recombination of O-atoms. The density of O- negative ions is very high in the plasma, the electronegativity of the discharge can be higher than 1, depending on the discharge conditions.

Original languageEnglish
Article number175201
JournalJournal of Physics D: Applied Physics
Volume43
Issue number17
DOIs
Publication statusPublished - 2010

Fingerprint

Surface waves
surface waves
Microwaves
microwaves
Kinetics
Gas discharge tubes
dissociation
Electronegativity
Quartz
Electrons
Electron temperature
kinetics
Wave propagation
Carrier concentration
tubes
Negative ions
Electric fields
gas discharge tubes
sustaining
Plasmas

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

Theoretical insight into Ar-O2 surface-wave microwave discharges. / Kutasi, K.; Guerra, Vasco; Paulo, S. A.

In: Journal of Physics D: Applied Physics, Vol. 43, No. 17, 175201, 2010.

Research output: Contribution to journalArticle

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