MARFE phenomena in the HT-7 tokamak

• Published in: Journal of nuclear materials Vol. 279; no. 2; pp. 330 - 334
• Main Authors: Gao, X, Luo, J.R, Zhao, Y.P, Qiu, N, Jie, Y.X, Yang, Y, Xia, C.Y, Wan, B.N, Kuang, G.L, Zhang, X.D, Li, J.G, Yin, F.X, Liu, X.N, Gong, X.Z, Zhang, S.Y, Zhao, J.Y, Hu, L.Q, Wu, Z.W, Li, Y.D, Yang, K, Bao, Y, Ye, W.W, Chen, L, Fan, H.Y, Liu, S.X, Chen, Y.F, Lin, B.L, Xu, Y.H, Shi, Y.J, Song, M, Zhang, X.M, Wei, M.S, Zeng, M, Xie, A.G, Cui, N.Z, Ruan, H.L, Wang, L, Sheng, B, Liu, S, Tong, X.D, Gu, X.M, Mao, J.S, Xie, J.K, Wan, Y.X
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2000; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Installations for energy generation and conversion: thermal and electrical energy; I02; P05; P06; L02; Tokamak; Nuclear fusion reactor; Asymmetry; Impurity density; Radiation; Surface plasma interaction; Experimental study
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/S0022-3115(99)00287-1

Multifaceted asymmetric radiation from the edge (MARFE) phenomena on the HT-7 superconducting tokamak are summarized in this paper. The best correlation has been found between the total input ohmic power and the product of the edge line average density and Z eff. The occurrence of MARFEs are strongly correlated with impurity density, and always occur at Z eff=3–8 ohmic discharges. In the HT-7 tokamak high Z eff discharges, it is found that the MARFEs usually occur at values of Z eff 1/2 ρ in the range of 0.5–0.7, where ρ=π a 2 n e/ I p (10 20 MA −1 m −1). In the case of good wall condition ( Z eff=1–2), the onset of MARFEs have not been observed before reaching the Greenwald density limit on the HT-7. Improved confinement mode induced by a MARFE is observed, and it is maintained for about 40 ms. MARFE cools the plasma edge, and the electron density profile is observed to become more narrow and peaked.