Effects of recycling neutral on density shoulder formation in tokamak plasmas

Nuclear Fushion

article

Xingquan Wu¹  Guosheng Xu¹  Ning Yan¹  Ran Chen¹  Liang Wang¹  Baonian Wan¹ 

[1] Institute of Plasma Physics, Chinese Academy of Sciences

关键词: tokamak divertor;    density shoulder;    effective ionization source;    neutral recycling;   

DOI  :  10.1088/1741-4326/ac3a1c

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Towards a physical understanding of the formation of flattened upstream scrape-off-layer (SOL) density profiles, namely 'density shoulders', a self-consistent one-dimensional radial transport model has been developed to estimate the upstream profiles covering both the core plasma and SOL region at the tokamak midplane. For the SOL region, the effective density and temperature profiles for the ionization process are obtained by the weighted averaging of the upstream and downstream profiles, which can distinguish the open-target operation from the closed-target operation by a weighting factor. Compared with enhanced turbulent convective transport, it is complementary for the model to study the competition between the effective sourceS _eff and the parallel particle lossL _SOL. It indicates that: (1) an appropriateS _eff intensity controlled by the neutral pressure due to divertor or wall recycling and (2) an appropriateS _eff peak position in a far SOL region adjusted by the plasma current as well as the weighting factor could offset the damping effect ofL _SOL on the density profile. ThenS _eff overL _SOL in a far SOL region could be the sole process involved in bringing about SOL density shoulders.

【 授权许可】

Unknown