Identification of I-mode with ion ITB in NBI-heated plasmas on the HL-2A tokamak

Nuclear Fushion

article

A.S. Liang¹  X.L. Zou²  W.L. Zhong¹  G.L. Xiao¹  R. Ke¹  X.X. He¹  Z.J. Li¹  M. Jiang¹  Z.C. Yang¹  P.W. Shi¹  J. Wen¹  G.Q. Xue¹  Y.R. Zhu¹  R.H. Tong¹  B.D. Yuan¹  J. Yin¹  L.Z. Liu¹  Z.Y. Yang¹  B. Li¹  W. Chen¹  D.L. Yu¹  Z.B. Shi¹  M. Xu¹  X.R. Duan¹ 

[1] Southwestern Institute of Physics;CEA;Dalian University of Technology

关键词: I-mode;    WCM;    ion-ITB;   

DOI  :  10.1088/1741-4326/acc25d

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Improved energy confinement mode (I-mode) has been observed on the HL-2A tokamak. The I-mode features an edge transport barrier (ETB) in electron temperature and a low confinement mode like edge density. A weakly coherent mode (WCM) is observed in the edge region with the frequency of fsim 60{-}160kHz and the poloidal wavenumber of {k_heta }sim 0.5{-}2.5{ext{cm}}{^{ - 1}} . The maximum of WCM amplitude is located near the top of electron temperature pedestal. A critical value of E imes Bvelocity shear for triggering the L–I transition has been found, and is much lower than that for triggering the L–H transition. Additionally, ion internal transport barrier (ITB) has been observed in the I-mode. The formation of ion ITB is due to the increase of E imes Bvelocity shear, leading to the suppression of turbulence. Transport analysis further confirms the existence of electron ETB and ion ITB. The coexistence of electron ETB and ion ITB leads to an improved plasma confinement, which is comparable to that in the high confinement mode, suggesting that I-mode with ITB regimes could be an interesting operation scenario for future fusion devices.

【 授权许可】

Unknown