Measurements of atomic nitrogen distributions in a radio-frequency atmospheric-pressure plasma jet

POSTER

Abstract

Radio-frequency (RF) driven atmospheric-pressure plasma jets (APPJs) are expected to have a range of new healthcare applications. To guarantee the effectiveness and safety of these devices, a thorough understanding of the physics and chemistry of these plasmas is needed. We studied an RF-APPJ in helium with small admixtures of nitrogen and/or oxygen. The low-temperature APPJ effluent contains high concentrations of reactive species such as atomic nitrogen and oxygen. The N and O radicals play a crucial role in the plasma chemistry and discharge dynamics, but are unfortunately difficult to measure experimentally. We present a two-photon absorption laser-induced fluorescence (TALIF) technique for measuring atomic nitrogen species, which uses 207 nm photons for excitation of ground-state N atoms and observes time-resolved fluorescence at 745 nm. With this diagnostic we directly measure the spatial and temporal evolution of atomic nitrogen species, and compare these to the results of a numerical model based on hydrodynamic equations with a semi-kinetic treatment of the electrons.

Authors

  • Erik Wagenaars

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

  • Kari Niemi

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

  • Deborah O'Connell

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

  • Timo Gans

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