Radiative divertor behavior and physics in Ar seeded plasma on EAST

Chen Jingbo^{1, 2}, Duan Yanmin¹, Yang Zhongshi^{1, 2, †}, Wang Liang¹, Wu Kai^{1, 2}, Li Kedong^{1, 2}, Ding Fang¹, Mao Hongmin¹, Xu Jichan^{1, 2}, Gao Wei¹, Zhang Ling¹, Wu Jinhua¹, Luo Guang-Nan^{1, 2}, EAST Team

(color online) Time traces of H-mode discharge with Ar seeding. The Ar mixture was seeded from the upper outer divertor target, and it started to function at 5.1 s owing to the delay of pipe length. (a) Plasma line-averaged density. (b) Ar/D₂ mixture seeding rate. (c) Stored energy of plasma. (d) Midplane, upper divertor, lower divertor region line integrated radiation, and total radiation power. (e), (f), (g) Emission intensities of impurity in the upper divertor region, measured using filterscope arrays. Note that the WI+ArII signal may contain two types of impurity: WI (400.87 nm) and ArII (401.38 nm), because the system cannot well distinguish these two spectral lines. (h) Ion saturation current in outer and inner divertor regions.