Compatibility of large ELM control and stable partial detachment with neon/argon seeding in EAST

Nuclear Fushion

article

K. Li¹  X. Lin¹  Z. Yang¹  Q. Yang¹  G. Xu¹  L. Meng¹  Y. Wang¹  H. Lan²  B. Zhang¹  L. Xu¹  K. Wu¹  T. He¹  J. Xu⁵  J. Wu¹  F. Ding¹  Y. Duan¹  S. Mao¹  Q. Zang¹  L. Zhang¹  T. Zhang¹  F. Wang¹  L. Wang¹  G.-N. Luo¹ 

[1] Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences;College of Physics and Optoelectronic Engineering, Shenzhen University;Advanced Energy Research Center, Shenzhen University;Science Island Branch of Graduate School, University of Science & Technology of China;School of Mechanical Engineering, Anhui University of Science & Technology

关键词: large ELM control;    partial detachment;    Ar/Ne seeding;    EAST tokamak;   

DOI  :  10.1088/1741-4326/acae36

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

It is necessary to achieve simultaneous exhaust of excessive transient and steady-state heat fluxes on the divertor target for the divertor protection in the future fusion reactors. The sustained large ELM control and stable partial detachment have been achieved concurrently with argon (Ar) or neon (Ne) seeding in EAST. With Ne seeding, the large ELMs with frequencyf _ELM ∼ 100 Hz disappear and a stable ELM-free state withH _{98, y 2} > 1 is maintained. Meanwhile, the electron temperatureT _et around the lower outer strike point decreases from more than 70 eV during the large ELM burst to less than 5 eV in the stable ELM-free phase. In addition, a slight improvement of plasma confinement is observed in the partially detached state, mainly attributed to the increased electron densityn _e and ion temperatureT _i in the core region. In the pedestal region, the density gradient and the electron temperature show subtle variation. The effective charge numberZ _eff increases significantly after Ne seeding, leading to a decrease in the edge bootstrap current and the pedestal pressure gradient, and thus the stabilization of ELMs. With Ar seeding, the large ELMs are also suppressed at first, but soon transit to type-III ELMs with a highf _ELM ∼ 1 kHz, highly correlated with the energy confinement degradation. The steady-state and transient heat fluxes on the divertor can be both well reduced with Ar/Ne seeding in EAST.

【 授权许可】

Unknown