Two dimensional simulations of the vibrational state distributions in low pressure hydrogen plasmas with an isothermal neutral gas and gas temperature gradients

ORAL

Abstract

Low pressure hydrogen plasmas are of interest in fundamental plasma phenomena and applications including surface processing and negative ion beams. As negative ions form in the plasma volume through dissociative attachment of vibrationally excited hydrogen molecules, it is important to understand their response to gas temperature gradients, known to form at high power densities. In this study, two dimensional fluid-kinetic simulations using the Hybrid Plasma Equipment Model, including a new reaction set that accounts for gas temperature dependencies in determining heavy particle reaction rates with all of the vibrational levels of the ground electronic state, are used to study the influence of these temperature gradients. The results demonstrate that the incorporation of spatially resolved gas temperatures has a significant impact on the distribution of atomic hydrogen and the vibrational states, but has a relatively smaller impact on the negative ions. These results are important for future studies of low pressure hydrogen plasmas in technological plasma sources that generate spatial gas temperature gradients.

*The authors would like to acknowledge Erik Wagenaars and Pascal Chabert for useful discussions. The work presented herein was funded by the Engineering and Physical Sciences Research Council (EPSRC), grant reference number EP/L01663X/1. The participation of V. Guerra was supported by the Portuguese FCT, under Projects UIDB/50010/2020 and UIDP/50010/2020. The participation of M. Kushner was supported by the US National Science Foundation and the US Department of Energy's Office of Fusion Energy Science.

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Presenters

  • Gregory J Smith

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

Authors

  • Gregory J Smith

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

  • Paola Diomede

    • Maastricht University
    • Faculty of Science and Engineering, Maastricht University, 6200 MD Maastricht, The Netherlands

  • Andrew Gibson

    • Ruhr University Bochum
    • Institute for Electrical Engineering, Ruhr-University Bochum, D-44801 Bochum, Germany

  • Scott J Doyle

    • Department of Atomic, Molecular and Nuclear Physics, University of Seville, Avda. Reina Mercedes, E-41012 Seville, Spain
    • Universidad de Sevilla

  • Vasco Guerra

    • Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Portugal
    • Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
    • Instituto de Plasmas e Fusãão Nuclear, Instituto Superior Técnico, Universidade de Lisboa 1049-001 Lisboa, Portugal
    • IPFN

  • Mark J Kushner

    • University of Michigan
    • University of Michigan, Ann Arbor
    • Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave, Ann Arbor, MI 48109-2122, United States of America

  • Timo Gans

    • School of Physical Sciences \& National Centre for Plasma Science and Technology (NCPST), Dublin City University, Dublin 9, Ireland

  • James P Dedrick

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