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A space-resolved EUV spectrometer for measuring the one-dimensional distribution of impurity line emissions in Large Helical Device (LHD) has been upgraded to measure two- dimensional distributions of impurity line emissions with an extension of working wavelength range to 30～650 A. The two-dimensional measurement is performed by scanning the observation chord horizontally. A rectangular plasma region of 520 × 700 mm 2 in vertical and horizontal sizes can be observed during a single horizontal scan. The horizontal scan requires a time duration of 5 s at least. The spatial resolution is 10 mm in the vertical direction when a spatial-resolution slit of 0.2 mm in width is adopted. Although a spatial resolution in the toroidal direction is 75 mm, it is a function of CCD exposure time and horizontal scanning speed. Two-dimensional distribution of EUV line emissions from several impurities has been successfully observed for the first time from steady discharges in LHD. In this paper two-dimensional distributions of He II (303.78 A), C V (40.27 A), C VI (33.73 A) and Fe XX (132.85 A) located at different radial positions are presented with simple analysis on the magnetic field structure of LHD.
A space-resolved EUV spectrometer for measuring the one-dimensional distribution of impurity line emissions in Large Helical Device (LHD) has been upgraded to measure two-dimensional distributions of impurity line emissions with an extension of working wavelength range of 30-650 A. The two-dimensional measurement is performed by scanning the observation chord horizontally. A rectangular plasma region of 520 × 700 mm 2 in vertical and horizontal sizes can be observed during a single horizontal scan. The horizontal scan requires a time duration of 5 s at least . The spatial resolution is 10 mm in the vertical direction when a spatial-resolution slit of 0.2 mm in width is adopted. Although a spatial resolution in the toroidal direction is 75 mm, it is a function of CCD exposure time and horizontal scanning speed. Two-dimensional distribution of EUV line emissions from several impurities has been successfully observed for the first time from steady discharges in LHD. In this paper two-d imensional distributions of He II (303.78 A), C V (40.27 A), C VI (33.73 A) and Fe XX (132.85 A) located at different radial positions are presented with simple analysis on the magnetic field structure of LHD.