Experimental progress of hybrid operational scenario on EAST tokamak

Nuclear Fushion

article

X. Gao¹  L. Zeng²  M.Q. Wu¹  T. Zhang²  Y. Yang²  T.F. Ming²  X. Zhu¹  Y.M. Wang²  H.Q. Liu²  Q. Zang¹  G.Q. Li²  J. Huang²  X.Z. Gong²  Y.Y. Li²  J.G. Li¹  Y.X. Wan¹  the EAST team² 

[1] Advanced Energy Research Center, Shenzhen University;Institute of Plasma Physics, Chinese Academy of Sciences;Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University

关键词: EAST;    high normalized beta;    fishbone;    power threshold;   

DOI  :  10.1088/1741-4326/abaa91

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Extensive experiments of advanced scenario development, which contribute to the ITER hybrid operational scenario have been carried out on experimental advanced superconducting tokamak (EAST) tokamak recently with the ITER-like tungsten divertor. The {beta _N}in this operational scenario is intermediate up to 2.1 (EAST#78987, {beta _N}∼ 2.1,I _p ∼ 0.45 MA,q ₉₅ = 3.7, {B_T}∼ 1.5 T, 3 MW neutron beam injection and 1 MW 4.6 GHz lower hybrid wave). In these hybrid H-mode plasmas, the internal transport barrier (ITB) has been frequently observed with central flatqprofile and it is found that the fishbone mode ( m / n= 1/1) can be beneficial to sustain the central flat ( q (0) ∼ 1)qprofile, thus a stable ITB can be obtained. In this case, better plasma performance is achieved. The formation of the ITB of the electron density is related to the fishbone activities. Energy transport analysis shows that the fishbone instabilities have a suppression on electron turbulent energy transport, while the ITB of ion temperature is due to the suppression of high-k modes (electron temperature gradient). The mechanism of turbulence suppression from fishbone instabilities in the EAST tokamak is not clear and needs more investigation. It is also observed that the power threshold for ITB formation is geq 3.5 MW, which is consistent with the scaling law for other tokamaks. The dimensionless parameter G{ext{ }} (= {ext{ }}{H_{89}}{beta _N}/q_{95}^2 ) obtained in the EAST reaches 0.3, but is still lower than the ITER hybrid scenario design ( G≥ 0.4) and needs more extension. Further investigation of extending the operational regimes, such as expanding the ITB foot outwards, would be important for the development of the hybrid and steady-state scenarios for next-step fusion devices like ITER and CFETR.

【 授权许可】

Unknown