Plasma and Fusion Research

Volume 10, 3402041 (2015)

Regular Articles

Hydrogen Atomic and Molecular Emission Locations and Intensities in the LHD Edge Plasma Determined from Simultaneously Observed Polarization Spectra

Keisuke FUJII, Keiji SAWADA¹⁾, Motoshi GOTO²⁾, Shigeru MORITA²⁾ and Masahiro HASUO

: Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8540, Japan
1): Department of Applied Physics, Faculty of Engineering, Shinshu University, Nagano 380-8553, Japan
2): National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan

(Received 25 November 2014 / Accepted 12 March 2015 / Published 16 April 2015)

Abstract

We observed polarization-resolved emission spectra of the Balmer-α, -β, and -γ lines of hydrogen atoms and the Q branches of the Fulcher-α band of hydrogen molecules simultaneously with six lines of sight in a poloidal cross section of the Large Helical Device (LHD). From the fit of the spectra including the line splits and their polarization dependence due to the Zeeman effect, we determined the emission locations, intensities and temperatures of the atoms and molecules. The determined emission locations of the hydrogen atoms were just outside the last closed flux surface and the intensities showed small dependence on the location. The emission locations of the molecules were rather around the divertor legs and their emission intensities showed location dependences. The determined atomic temperature was about 1 eV and the molecular rotational temperature was 0.04∼0.07 eV, both of which showed no systematic dependence on the location within the experimental accuracy.

Keywords

Polarization spectroscopy, Balmer emission spectra, Fulcher-α emission spectra, Zeeman effect, Emission locations and intensities, LHD edge plasma

DOI: 10.1585/pfr.10.3402041

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This paper may be cited as follows:

Keisuke FUJII, Keiji SAWADA, Motoshi GOTO, Shigeru MORITA and Masahiro HASUO, Plasma Fusion Res. 10, 3402041 (2015).