Impurity spectroscopy in fusion plasmas and plan for A3 collaboration

A comparative study of the edge impurity transport is attempted between different edge magnetic field geometries by comparing the stochastic layer of Large Helical Device (LHD) and the scrape-off layer of Huan Liuqi-2A (HL-2A) tokamak. For the purpose carbon emission profiles are measured in LHD and HL-2A using extreme ultraviolet (EUV) and vacuum ultraviolet (VUV) spectrometers. In LHD two EUV spectrometers are working in 10-100 and 50-650 wavelength ranges. The radial profiles and two-dimensional profiles are also measured with excellent absolute calibration of the spectrometer system. In HL-2A 1m VUV spectrometer is working to measure the radial profile and recently EUV spectrometer is also start to work. The analysis is based on the 3D edge fluid transport code simulation, EMC3 - EIRENE, which is implemented in the both devices. (J.P.N.)