Radiative divertor detachment with impurity seeding is considered one of the most promising means for mitigating particle and heat fluxes on the divertor target. To measure the impurity radiation distribution, a tangentially viewing camera system for lower divertor plasma observation has been developed and installed on EAST. A reconstructed 2D distribution of N II line radiation is obtained based on Phillips–Tikhonov regularization, revealing the electron temperature region in the range of 6–10 eV during a nitrogen (N2) seeding experiment. With N2 seeding, the deep detachment with the stable X-point radiator (XPR) has been achieved on EAST with a tungsten divertor and metal first wall components. The profiles of Tet and qt with a distance to the strike point larger than 6 cm (ρ ∼ 1.06) are radially flat on the outer divertor target in the deeply detached state. The XPR contributes to the effective divertor protection with mitigation of heat/particle fluxes and suppression of divertor target sputtering.
This paper investigates the use of radiative divertor detachment with impurity seeding to mitigate particle and heat fluxes on the divertor target in the EAST tokamak. The study reveals the formation of a stable X-point radiator (XPR) during nitrogen seeding, leading to effective divertor protection by reducing heat/particle fluxes and suppressing divertor target sputtering.