Particle exhaust and recycling control by active divertor pumping in EAST

Abstract The EAST tokamak was built to carry out long pulse plasma discharges up to 1000 s. To facilitate this, an active divertor pumping (ADP) system was installed under the lower outer (LO) divertor target plate (DTP) for plasma density control and impurity exhaust. The ADP system was used in the first EAST divertor physics campaign, and achieved very promising results on neutral gas particle exhaust and recycling control. The system can improve divertor screening for neutrals and reduce the ratio H/(H + D), and appears to be effective at controlling the main chamber hydrogenic recycling. The influence of ADP on lower inner (LI) and LO DTP is observed. Furthermore, we attempt to find an optimized strike point to mitigate DTP heat load during ADP operation. This article reports on these interesting results, in particular, for the lower single null (LSN) plasma configuration.