Advanced Divertor Studies in EAST/DIII-D by SOLPS

Divertor is one of the key components in Tokamak. The design, construction and operation of advanced divertors have been the main topics of tokamak research during the last decade. In general, developing an advanced divertor configuration requires: (1)Optimizing magnetic configuration to extend the plasma-wetted area through flux expansion, and increasing the divertor volume by increasing the field-line length;(2)Increasing divertor closure by divertor baffling to improve divertor screening for recycling neutrals and impurities, hence increasing divertor neutral pressure, thus enhancing divertor particle and power exhaust. In the present work, some advanced divertor solutions are developed and validated in EAST and DIII-D respectively. In EAST an alternative advanced divertor configuration, i.e., quasi snowflake (QSF), aka X-divertor and in DIII-D an alternative advanced divertor coupling divertor closure with advanced magnetic configuration(X-divertor) have been attempted respectively. The findings indicate that the advanced divertor solutions in EAST and DIII-D can significantly reduce the peak heat flux density at the divertor target and the density threshold for detachment, which provides a promising means for the design of advanced divertors in the next-step fusion devices.