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Title: Comparison of gridded energy analyzer and laser induced fluorescence measurements of a two-component ion distribution

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.2953411· OSTI ID:21266632
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  1. Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

We present ion velocity distribution function (IVDF) measurements obtained with a five grid retarding field energy analyzer (RFEA) and IVDF measurements obtained with laser induced fluorescence (LIF) for an expanding helicon plasma. The ion population consists of a background population and an energetic ion beam. When the RFEA measurements are corrected for acceleration due to the electric potential difference across the plasma sheath, we find that the RFEA measurements indicate a smaller background to beam density ratio and a much larger parallel ion temperature than the LIF. The energy of the ion beam is the same in both measurements. These results suggest that ion heating occurs during the transit of the background ions through the sheath and that LIF cannot detect the fraction of the ion beam whose metastable population has been eliminated by collisions.

OSTI ID:
21266632
Journal Information:
Review of Scientific Instruments, Vol. 79, Issue 10; Conference: HTPD08: 17. topical conference on high-temperature plasma diagnostics, Albuquerque, NM (United States), 11-15 May 2008; Other Information: DOI: 10.1063/1.2953411; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
Country of Publication:
United States
Language:
English