Two-dimensional measurement of edge impurity emissions using space-resolved extreme ultraviolet spectrometer in Large Helical Device

A space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 50-500 A has been developed to measure two-dimensional distribution of impurity spectral lines emitted from edge plasma of Large Helical Device (LHD), in which the magnetic field is formed by stochastic magnetic field with three-dimensional structure called ergodic layer. The two-dimensional measurement of edge impurity line emissions is carried out by scanning horizontally the observation chord of the space-resolved EUV spectrometer during single LHD discharge. Images of CIV (312.4 A) and HeII (303.78 A) are presented as the first result. The results are compared with ones calculated from the edge chord length in the ergodic layer of LHD plasma.