Estimation of density profiles of W⁴³⁺ - W⁴⁵⁺ in EAST H-mode plasma

In order to study the behavior and radial transport of tungsten ions in long-pulse H-mode plasmas, a space-resolved spectrometer working at 30-520Å has been newly developed to measure a radial profile of the tungsten line emission. The radial profiles of tungsten line emissions from W⁴²⁺ - W⁴⁵⁺ ions with 4p-4s and 4d-4p transitions measured at 45-70Å and 120-140Å are analyzed for the ion density evaluation based on the photon emissivity coefficient from ADAS database. The result shows that the densities of W⁴³⁺ - W⁴⁵⁺ ions range at 2-6×10⁸ cm^-3 in steady H-mode discharges with T_e(0)=3 keV and n_e(0)=4×10¹³ cm^-3. (author)