The transport of tungsten impurities induced by the intrinsic carbon during upper-single null discharge on EAST tokamak

Nuclear Materials and Energy

Guoliang Xu¹  Rui Ding²  Xuele Zhao²  Chaofeng Sang³  Yilin Wang³  Dezhen Wang³  Qingrui Zhou³ 

[1] Corresponding author.;Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China;Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China;

关键词: Divertor;    Target erosion;    Tungsten impurity transport;    Power radiation;   

DOI  :  

来源: DOAJ

【 摘 要 】

The transport as well as accumulation of tungsten (W) impurity is one of the critical issues for the W divertor operation. The EAST tokamak with W and graphite divertor targets, provides a good platform for the investigation of W impurity behaviors. In this work, the production, transport and accumulation of W impurities are simulated via the SOLPS-DIVIMP modeling. The plasma background is obtained by the SOLPS simulations, while the W sputtering yield is calculated via empirical formula, and the following W transport is traced using the DIVIMP code. The W impurity source is mainly contributed by the incidence of carbon (C) impurity in this simulation. The distribution of W ions with different charge states is obtained and the transport of the W ions is analyzed by the net forces. The dependences of W impurity on the ne,sepOMP and PSOL are illustrated, which show the divertor plasma has great impact on the W impurity distribution. The increase of ne,sepOMP can suppress the W impurity in the core region with the fixed PSOL, while higher input power can enhance the W concentration significantly. The W impurity can lead to sufficient power radiation due to strong impurity source and high radiation rate in the core region during low density discharge, while the influence becomes weaker as ne,sepOMP raises. The effects of self-sputtering on the W impurity accumulation are also discussed. With the increment of PSOL, the sputtering and self-sputtering of W increase remarkably, leading to the W ions concentration exceed 10−5 in the core–edge interface (CEI). Moreover, the strong correlation between Te at the outer target and W ion density at CEI is observed, showing that Te < 20 eV is required to maintain W concentration at CEI below the acceptable limitation (10−5) in steady-state scenarios in EAST (without ELMs).

【 授权许可】

Unknown