Characterization of the JT-60U divertor plasma region during the formation of a strong radiation

Koubiti, M.*; Nakano, Tomohide; Capes, H.*; Marandet, Y.*; Mekkaoui, A.*; Mouret, L.*; Rosato, J.*; Stamm, R.*

The spectral profile of C IV (=6-7) measured from the strong radiation zone (X-point MARFE) in a detached plasma of JT-60U with a high resolution spectrometer was analyzed by PPP code. In the previous analysis, a spectral profile calculated by the PPP code with an input of single pair of electron density and temperature was compared to the measured spectral profile. It was found that the spectral profiles measured around the X-point MARFE were reproduced with the calculated spectral profile but the ones measured at the center of the X-point MARFE were not. In the present analysis, two spectral profiles were calculated with two pairs of electron density and temperature and were summed up, leading to successful reproduction of the measured spectral profile. The two pairs of electron density and temperature used for the calculation were 110 m and 23.0 eV, and 610 m and 2.5 eV, respectively, with a mixture ratio of 65:35.