Plasma and Fusion Research

Volume 3, S1042 (2008)

Regular Articles

Ionization Balance in the Rotating Radiation Belt Accompanying Complete Divertor Detachment in LHD
Motoshi GOTO and Shigeru MORITA
National Institute for Fusion Science, Toki 509-5292, Japan
(Received 16 November 2007 / Accepted 15 February 2008 / Published 1 August 2008)

Abstract

A spectroscopic measurement is performed for a plasma in a rotating radiation belt, which accompanies the complete divertor detachment recently realized in the Large Helical Device (LHD) [J. Miyazawa et al., Nucl. Fusion 46, 532 (2006)]. The population distribution over the exited levels is experimentally determined from the Balmer series line intensities and is compared with the result of the collisional-radiative model calculation to determine the electron temperature Te and density ne. No reasonable pair of Te and ne is found when either the ionizing plasma or the recombining plasma is assumed. A good fitting is obtained under an assumption of the ionization balance plasma with Te = 1.8 eV and ne = 2 × 1020 m-3. These parameters are confirmed through analysis of a high-wavelength-resolution measurement for the Balmer series lines which clearly exhibit the Stark broadening effect.

Keywords

radiation belt, spectroscopy, ionization balance plasma, Stark broadening

DOI: 10.1585/pfr.3.S1042

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This paper may be cited as follows:

Motoshi GOTO and Shigeru MORITA, Plasma Fusion Res. 3, S1042 (2008).