Helium line intensity ratio in microwave-generated plasmas

N. K. Podder, J. A. Johnson, C. T. Raynor, S. D. Loch, C. P. Ballance, M. S. Pindzola

Research output: Chapter in Book/Report/Conference proceedingChapter

21 Citations (Scopus)

Abstract

The line intensity ratio method provides a nonintrusive diagnostic for the measurement of electron temperature in microwave-generated plasmas. For optically thin plasmas of low density, a line intensity method using He I lines can often be used, and is based on the fact that the electron impact excitation rate coefficients for helium singlet and triplet states are insensitive to electron density but differ as a function of the electron temperature. Line intensity measurements are presented from microwave-generated helium plasmas. Both steady-state corona and collision-radiative theoretical models are used to evaluate the ground and excited state populations. The line ratio versus electron temperature obtained from both of these methods are compared with the results from measurements. However, it is not possible to diagnose the electron temperature from the line ratios alone due to the presence of significant opacity and nonnegligible 1s2s S-3 metastable fraction in the plasma. (C) 2004 American Institute of Physics.
Original languageEnglish
Title of host publicationPhysics of Plasmas
Pages5436-5443
Number of pages8
DOIs
Publication statusPublished - 2004

Publication series

NamePhysics of Plasmas
Volume11

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