Characteristics of electron temperature profile stiffness in electron-heated plasmas on EAST
| Autor: | J.W. Liu, Q. Zang, Y. Liang, Y.H. Huang, E.Z. Li, L.Q. Xu, A. Knieps, Y.Q. Chu, Y. Chao, Y.C. Hu, Y.F. Jin, H.Q. Liu, H.L. Zhao, B. Lyu, X.Z. Gong, the EAST Team |
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| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Nuclear Fusion, Vol 63, Iss 1, p 016011 (2022) |
| Druh dokumentu: | article |
| ISSN: | 1741-4326 0029-5515 01402455 |
| DOI: | 10.1088/1741-4326/aca168 |
| Popis: | A very high core electron temperature ( T _e0 ∼ 10 keV) plasma has been established and stably sustained by applying both lower hybrid wave (LHW) and on-axis electron cyclotron resonance heating (ECRH) in the Experimental Advanced Superconducting Tokamak (EAST). In this work, power balance analysis shows that the increase of ECRH power can increase the normalized T _e gradient significantly at the plasma core region ( ρ < 0.6), but does not change the T _e profile stiffness in the low-density L-mode plasmas. This has been considered to be due to a strong synergistic effect between ECRH and LHW. Furthermore, three distinguishable stages characterized by different T _e profile stiffnesses can be identified from the density ramp-up in the electron-heated plasma on EAST. A stronger T _e profile stiffness at ρ = 0.3 has been observed in the Stage-II, where the LHW power deposition gradually moves away from the plasma core region, following the electron density increases. Furthermore, the formation of an internal plasma density transport barrier inside ρ ∼ 0.6, accompanied by a sudden drop in core T _e and a rise in both core plasma density and ion temperature, has been observed for the first time during the transition from the Stage-II to the Stage-III when the central line-averaged plasma density reaches a threshold of 2.2 × 10 ^19 m ^−3 . This finding strongly affects further development of high-performance gas-fueled electron-heated plasma scenarios in EAST and suggests an advanced operational regime with a wide internal plasma density transport barrier. |
| Databáze: | Directory of Open Access Journals |
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