[Table of Contents]

Plasma and Fusion Research

Volume 5, S1021 (2010)

Regular Articles

Application of Zeff Profile Analysis Based on Visible Bremsstrahlung Measurement to Different Density Profiles in the LHD
Hangyu ZHOU, Shigeru MORITA1), Motoshi GOTO1), Kazumichi NARIHARA1) and Ichihiro YAMADA1)
Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu, Japan
National Institute for Fusion Science, Toki 509-5292, Gifu, Japan
(Received 11 January 2009 / Accepted 8 June 2009 / Published 26 March 2010)


Visible bremsstrahlung emission has been measured along the vertical direction of a horizontally elongated plasma cross section in a range of −0.6 m ≤ z ≤ 0.0 m from an inwardly shifted (Rax ≤ 3.6 m) configuration by means of an optimized Czerny-Turner spectrometer installed on the Large Helical Device. Chord-integrated bremsstrahlung intensity profiles have been observed in discharges having no asymmetric strong edge bremsstrahlung emission originating in the ergodic layer. Radial bremsstrahlung emission profiles are obtained from the chord-integrated profiles based on an Abel inversion method. Zeff profiles are thus analyzed for peaked, flat, and hollow density profiles, which are measured with a Thomson scattering diagnostic, as the first trial of the analysis. As a result, a flat Zeff profile is obtained for all different density profiles with values of 1 < Zeff ≤ 2. This indicates that the partial impurity pressure is essentially constant against the plasma radius.


Zeff profile, visible bremsstrahlung, density profile

DOI: 10.1585/pfr.5.S1021


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This paper may be cited as follows:

Hangyu ZHOU, Shigeru MORITA, Motoshi GOTO, Kazumichi NARIHARA and Ichihiro YAMADA, Plasma Fusion Res. 5, S1021 (2010).