Discharge dynamics in a helium capacitively coupled plasma with variable oxygen admixture

POSTER

Abstract

The discharge dynamics in a helium capacitively coupled plasma with variable oxygen admixture are investigated by means of a one-dimensional numerical fluid model with semi-kinetic treatment of electrons and accompanying phase and space resolved measurements. The discharge is operated at 40 Pa with a sinusoidal driving voltage at a frequency of 13.56 MHz and is solved self-consistently in the model for each individual RF-cycle. Spatial profiles of dominant charged particles (O2+, O-, e) in the gas mixture exhibit a distribution change under variation of the oxygen admixture. Discharge excitation dynamics, in particular of the atomic oxygen line $\lambda $ = 844 nm (3P -3S) are investigated and compared to those observed from experiments. The simulations show and experiments confirm that additional oxygen in the helium discharge significantly changes the excitation mechanisms and promotes the excitation from secondary electrons.

Authors

  • Arthur Greb

  • Kari niemi

    • Centre for Plasma Physics, Queens University Belfast, Belfast, BT7 1NN, Northern Ireland, UK
    • Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland, UK
    • Queens University Belfast
    • Centre for Plasma Physics, Queen's University Belfast, Belfast BT7 1NN, 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