Reactive species in atmospheric pressure helium-oxygen plasmas with humid air impurities

ORAL

Abstract

In most applications helium-based plasma jets operate in an open air environment. The presence of humid-air in the plasma jet will influence the plasma chemistry and can lead to the production of a broader range of reactive species. We explore the influence of humid air on the reactive species in rf driven atmospheric-pressure helium-oxygen mixture plasmas (helium with 5000 ppm admixture of oxygen) for wide air impurity levels of 0-500 ppm with relative humidities of from 0 to 100{\%} using a zero-dimensional, time-dependent global model. Comparisons are made with experimental measurements in an rf driven micro-scale atmospheric pressure plasma jet and with one-dimensional semi-kinetic simulations of the same plasma jet. The evolution of species concentration is described for reactive oxygen species, metastable species, radical species and positively- and negatively-charged ions (and its clusters). Effects of the air impurity containing water humidity on electronegativity and chemical activity are clarified with particular emphasis on reactive oxygen species.

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Authors

  • Tomoyuki Murakami

    Tokyo Institute of Technology

  • Kari Niemi

    University of York, York Plasma Institute, University of York, YO10 5DD, York, UK, York Plasma Institute, Department of Physics, University of York, York YO10 5DD, UK

  • Timo Gans

    University of York, York Plasma Institute, University of York, YO10 5DD, York, UK, York Plasma Institute, Department of Physics, University of York, York YO10 5DD, UK

  • Deborah O'Connell

    University of York, York Plasma Institute, University of York, YO10 5DD, York, UK, York Plasma Institute, Department of Physics, University of York, York YO10 5DD, UK

  • Bill Graham

    Queen's University Belfast