Spectroscopic Diagnostic of Helium-Hydrogen RF Plasma under the Influence of Radiation Trapping

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    • SAWADA Keiji
    • Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
    • GOTO Motoshi
    • National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
    • EZUMI Naomichi
    • Nagano National College of Technology, 716 Tokuma, Nagano 381-8550, Japan


The electron temperature and density, atomic hydrogen density and temperature in a helium-hydrogen RF plasma are determined from the visible emission line intensities of both atoms by considering photoexcitation from the ground state accompanied by radiation trapping in the plasma. From the observed helium line intensity, and the hydrogen Balmer γ line intensity which is little affected by photoexcitation, parameters other than the atomic hydrogen temperature are determined using a helium atom collisional-radiative model [Sawada et al., Plasma Fusion Res. 5, 001 (2010)], which includes photoexcitation for helium singlet P states, and a hydrogen atom collisional-radiative model in which photoexcitation is ignored. The atomic hydrogen temperature is determined to reproduce the Balmer α and β line intensities by using an iterative hydrogen atom collisional-radiative model [Sawada, J. Plasma Phys. 72, 1025 (2006)] that calculates the photoexcitation rates.


  • Plasma and Fusion Research

    Plasma and Fusion Research (6), 1401010-1401010, 2011

    The Japan Society of Plasma Science and Nuclear Fusion Research


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