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Indexed by:期刊论文

Date of Publication:2018-07-01

Journal:PHYSICS OF PLASMAS

Included Journals:SCIE

Volume:25

Issue:7

ISSN No.:1070-664X

Abstract:Tungsten (W) and Carbon (C) are, respectively, used as the plasma-facing materials for upper and lower divertors in EAST. This provides an opportunity to study the plasma performance with both W and C divertors simultaneously. In this work, simulations are carried out by using the edge fluid-plasma/kinetic-neutral code SOLPS5.0-EIRENE99, with emphasis on the C impurity transport and its effect on the power radiation and erosion of the upper W divertor target. Three typical magnetic field equilibrium configurations, i.e., lower single null, upper single null (USN), and double null (DN), are studied. The main deuterium (D) plasma and C impurities at each ionization state and their neutrals are considered in the simulation. The SOLPS output such as averaged incident ion energy and particle flux density of each species are used to calculate the erosion rate of W walls using the empirical formula for physical sputtering yield. The transport and performance of C impurities on different plasma conditions of each configuration are investigated by changing the C source strength and upstream plasma density. The upper W target erosion by C ions under different conditions is also evaluated. The simulation results indicate that (1) carbon is a strong radiator in EAST divertor temperatures of 10-20 eV; (2) the amount of carbon transported from the lower carbon divertor to the upper tungsten divertor in both USN and DN configurations is predicted to be too small to cause significant W sputtering; and (3) C6+ dominates upper W erosion in the DN case. (C) 2018 Author(s).