Radiative Divertor Plasma Behavior in L- and H-Mode Discharges with Argon Injection in EAST

Introducing strong radiative impurities into divertor plasmas has been considered as an important way to mitigate the peak heat load at the divertor target plate for ITER, and will be employed in EAST for high power long pulse operations. To this end, radiative divertor experiments were explored under both low (L) and high (H)-mode confinement regimes, for the first time in EAST, with the injection of argon and its mixture (25% Ar in D 2 ). The Ar injection greatly reduced particle and heat fluxes to the divertor in L-mode discharges, achieving nearly complete detached divertor plasma regimes for both single null (SN) and double null (DN) configurations, without increasing the core impurity content. In particular, the peak heat flux was reduced by a factor of ～6, significantly reducing the intrinsic in-out divertor asymmetry for DN, as seen by both the new infra-red camera and the Langmuir probes at the divertor target. Promising results have also been obtained in the H-modes with argon seeding, demonstrating a significant increase in the frequency and decrease in the amplitude of the edge localized modes (ELMs), thus reducing both particle and heat loads caused by the ELMs. This will be further explored in the next experimental campaign with increasing heating power for long pulse operations.     

EAST偏滤器充气系统标定

EAST偏滤器充气系统是辐射偏滤器研究的重要方面。本文详细介绍了EAST新一轮改造升级后偏滤器充气系统最重要的两个特性——充气阀流量率和管道延迟时间的标定,结果显示系统性能得到较好优化,流量率线性稳定,延迟时间缩短约一半左右。