Spatial and temporal evolution of electron density and plasma potential by resonance hairpin probe and emissive probe during pulsed laser photo-detachment of negative ions

ORAL

Abstract

Laser~photo-detachment is the most commonly used technique for measuring negative ion parameters. In this study we measured the electron density perturbation using a resonance hairpin probe and plasma potential using floating emissive probe along the path and outside the laser beam. Experiment is performed in a 13.56 MHz inductive RF discharge for various ranges of power and pressures. It is found that the plasma potential rises instantaneously for confining the photo-detached electrons and decays at a rate dictated by the diffusion of negative ions from the adjacent layer. This is found to be consistent with the spatial and temporal evolution of electron density.

*The project is funded by Euratom Association DCU fusion grant; contract number FU07-CT-2007-00052.

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Authors

  • N. Sirse

    • National Centre For Plasma Science and Technology, Dublin City University, Ireland

  • M.A. Mujawar

    • National Centre For Plasma Science and Technology, Dublin City University, Ireland
    • NCPST, Dublin City University, Dublin 9, Ireland

  • Jim Conway

    • National Centre For Plasma Science and Technology, Dublin City University, Ireland
    • Dublin City University

  • Miles Turner

    • Dublin City University
    • Dublin City University, Ireland
    • National Centre For Plasma Science and Technology, Dublin City University, Ireland
    • NCPST, Dublin City University, Dublin 9, Ireland
    • NCPST, School of Physical Sciences, DCU
    • NCPST, DCU

  • S.K. Karkari

    • Dublin City University, Ireland and Institute for Plasma Research, India
    • National Centre for Plasma Science and Technology, Dublin City University, Ireland and Institute for Plasma Research, Bhat, Gandhinagar, India
    • NCPST, Dublin City University, Dublin 9, Ireland \& Institute for Plasma Research, Bhat, Gandhinagar, Gujarat, India, 382428
    • National Centre For Plasma Science and Technology, Dublin City University, Ireland and Institute For Plasma Research, Bhat, Ghandhinagar, India