Plasma and Fusion Research

Volume 5, 032 (2010)

Regular Articles

Magnetic Axial Dependency of Hα Emission Location in Peripheral Plasmas of Large Helical Device as Determined by Plasma Polarization Spectroscopy

Atsushi IWAMAE, Atsushi SAKAUE, Nobuhiro NESHI, Jun YANAGIBAYASHI, Masahiro HASUO, Daisuke NAKAMURA¹⁾, Keiji SAWADA¹⁾, Motoshi GOTO²⁾ and Shigeru MORITA²⁾

: Department of Mechanical Engineering and Science Kyoto University, Kyoto 606-8501, Japan
1): Faculty of Engineering, Shinshu University, Wakasato, Nagano 380-8553, Japan
2): National Institute for Fusion Science, Toki, Gifu 509-5292, Japan

(Received 28 April 2010 / Accepted 14 July 2010 / Published 27 August 2010)

Abstract

The behavior of hydrogen neutral particles in and around the ergodic layer of Large Helical Device plasmas has been investigated through Hα emission spectral line profiles using plasma polarization spectroscopy (PPS). The PPS technique enables us to quantitatively evaluate emission locations, atomic temperatures and velocity components along the line-of-sight (LOS) for both inner and outer peripheral regions. The emission locations and the LOS components of atomic velocities are determined by varying the magnetic field axis R_ax from 3.60 m to 4.00 m, shot by shot. The high intensity region of Hα emissions is localized in the inner ergodic layer for the inward configuration. With an increase in R_ax, the high intensity region of Hα emission moves outward.

Keywords

hydrogen Balmer α, polarization, neutral particle transport, spectral line profile, peripheral plasma

DOI: 10.1585/pfr.5.032

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This paper may be cited as follows:

Atsushi IWAMAE, Atsushi SAKAUE, Nobuhiro NESHI, Jun YANAGIBAYASHI, Masahiro HASUO, Daisuke NAKAMURA, Keiji SAWADA, Motoshi GOTO and Shigeru MORITA, Plasma Fusion Res. 5, 032 (2010).