TECXY modelling studies of alternative EAST magnetic configurations

摘要

Introduction Several alternative magnetic divertor configurations have been proposed to handle high exhaust power. The majority of them relies on the presence of a second null, more or less close to the first one. The main physics difference being whether the flux lines converge or flare in front of the divertor plates. Several authors refer to experimental scenarios dedicated to the understanding of the role of the two nulls as quasi Snow Flakes (QSF) scenarios. The first experiments [1, 2] on the Experimental Advanced Superconducting Tokamak (EAST) were mainly devoted to study the feasibility of QSF configurations for different distances of the two nulls. This contribution reports on predictive and interpretative simulations focusing on the comparison of two QSF configurations versus a standard single null configurations (SN). Consistency is found between the experimental and calculated mitigation of the power load onto the divertor targets for a QSF at low scrape-off layer (SOL) density and low additional power. Predictions on how further mitigation can be achieved at high density will be presented together with preliminary studies on the reciprocal distance between the two produced nulls.