The influence of full drifts on density shoulder formation at the midplane by numerical modeling

Nuclear Fushion

article

Xuele Zhao¹  Chaofeng Sang¹  Ilya Yu. Senichenkov²  Yilin Wang¹  Yanjie Zhang¹  Chen Zhang¹  Vladimir Rozhansky²  Dezhen Wang¹ 

[1] Key Laboratory of Materials Modification by Laser, Ion and Electron Beams ,(Ministry of Education), School of Physics, Dalian University of Technology;Peter the Great St Petersburg Polytechnic University

关键词: drift;    density shoulder;    particle recycling;    ion sources;   

DOI  :  10.1088/1741-4326/ac9b77

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

The density shoulder at the midplane may influence core plasma confinement during H-mode discharge, thus affecting long-pulse steady-state discharge. Drifts in the edge plasma play a remarkable role in plasma transport and the divertor operation regime, which determine density shoulder formation (DSF). In this work, the SOLPS-ITER code package is used to evaluate the influence of full drifts on DSF in poloidal and radial coordinates. An open divertor of DIII-D-like geometry with weak neutral compression is chosen for the modeling. Cases without drifts, with onlyE × Bdrifts in forwardB _t and with full drifts in both forward and reversedB _t are simulated for comparison. It is confirmed that the high upstream density promotes DSF when the drift is not considered, which has also been observed in various investigations. When the drifts are taken into account, the divertor in/out asymmetry (or upstream ionization source) is determined by the direction ofB _t due to the variation of particle transport, thus the shoulder can be facilitated or suppressed. Two mechanisms of DSF with full drifts are elucidated: (1)E × BandB ×∇ Bdrifts promote DSF at the inner midplane (IMP) by raising the ionization source (at IMP) in forwardB _t; (2) the drifts contribute to DSF at the outer midplane by enhancing the particle transport loss in reversedB _t. In a high-recycling regime, ionization is the dominant term for DSF, while in the low-recycling regime enhanced particle transport loss plays a more important role. Comprehensively understanding the mechanisms of DSF is of great importance for the improvement of core–edge compatibility in fusion reactors.

【 授权许可】

Unknown