Long radial coherence of electron temperature fluctuations in non-local transport in HL-2A plasmas

• Published in: Chinese physics B Vol. 33; no. 2; pp. 25202 - 476
• Main Authors: Shi, Zhongbing, Fang, Kairui, Li, Jingchun, Zou, Xiaolan, Lu, Zhaoyang, Wen, Jie, Wang, Zhanhui, Ding, Xuantong, Chen, Wei, Yang, Zengchen, Jiang, Min, Ji, Xiaoquan, Tong, Ruihai, Li, Yonggao, Shi, Peiwan, Zhong, Wulyv, Xu, Min
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and IOP Publishing Ltd 01.02.2024
• Subjects: gas-puffing; non-local transport; nuclear fusion; tokamak; nuclear fusion; tokamak; gas-puffing; non-local transport
• ISSN: 1674-1056; 2058-3834; 2058-3834
• DOI: 10.1088/1674-1056/ad1093

The dynamics of long-wavelength ( k θ < 1.4 cm −1 ), broadband (20 kHz–200 kHz) electron temperature fluctuations ( T ∼ e / T e ) of plasmas in gas-puff experiments are observed for the first time in HL-2A tokamak. In a relatively low density ( n e (0) ≃ 0.91 × 10 19 m −3 –1.20 × 10 19 m −3 ) scenario, after gas-puffing the core temperature increases and the edge temperature drops. On the contrary, temperature fluctuation drops at the core and increases at the edge. Analyses show the non-local emergence is accompanied with a long radial coherent length of turbulent fluctuations. While in a higher density ( n e (0) ≃ 1.83 × 10 19 m −3 –2.02 × 10 19 m −3 ) scenario, the phenomena are not observed. Furthermore, compelling evidence indicates that E × B shear serves as a substantial contributor to this extensive radial interaction. This finding offers a direct explanatory link to the intriguing core-heating phenomenon witnessed within the realm of non-local transport.