Observation of Tungsten Line Emissions in Wavelength Range of 10 - 500 Å in Large Helical Device

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Author(s)

    • LIU Yang
    • Department of Fusion Science, Graduate University for Advanced Studies
    • MORITA Shigeru
    • Department of Fusion Science, Graduate University for Advanced Studies|National Institute for Fusion Science
    • OISHI Tetsutarou
    • Department of Fusion Science, Graduate University for Advanced Studies|National Institute for Fusion Science
    • GOTO Motoshi
    • Department of Fusion Science, Graduate University for Advanced Studies|National Institute for Fusion Science

Abstract

<p>Tungsten spectra have been observed in Large Helical Device (LHD) by injecting a coaxial tungsten pellet to identify the emission lines in extreme ultraviolet (EUV) range of 10 - 500 Å. The spectra of line emissions from tungsten ions have been measured in neutral-beam-heated discharges using two EUV spectrometers of EUV_Short and EUV_Long working in wavelength ranges of 10 - 130 Å and 50 - 500 Å, respectively. As a result, a lot of tungsten lines from low-ionized ions of W<sup>4+</sup>, W<sup>6+ </sup>and W<sup>7+ </sup>are observed for the first time in the toroidal device in addition to tungsten lines from highly ionized ions of W<sup>41+</sup>-W<sup>45+</sup>. Measured line emissions are carefully identified based on the NIST database and the determined wavelengths show a good agreement with the NIST database. The result is summarized in table with information on blended lines obtained from the radial profile measurement.</p>

Journal

  • Plasma and Fusion Research

    Plasma and Fusion Research 13(0), 3402020-3402020, 2018

    The Japan Society of Plasma Science and Nuclear Fusion Research

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