Multiscale interaction between a large scale magnetic island and small scale turbulence. (26th October 2017)

• Record Type: Journal Article
• Authors: Choi, M.J.; Kim, J.; Kwon, J.-M.; Park, H.K.; In, Y.; Lee, W.; Lee, K.D.; Yun, G.S.; Lee, J.; Kim, M.; Ko, W.-H.; Lee, J.H.; Park, Y.S.; Na, Y.-S.; Luhmann, N.C.; Park, B.H.
• Is Part Of: Nuclear fusion. Volume 57:Number 12(2017:Dec.)
• Publication Date: 2017-10-26
• Subjects: magnetic island -- turbulence -- multiscale interaction; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/aa86fe
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Multiscale interaction between the magnetic island and turbulence has been demonstrated through simultaneous two-dimensional measurements of turbulence and temperature and flow profiles. The magnetic island and turbulence can mutually interact via coupling between the electron temperature ( T e ) gradient, the T e turbulence, and the poloidal flow. The T e gradient altered by the magnetic island steepens outside and flattens inside the island. The T e turbulence can appear in increased T e gradient regions. The combined effects of the T e gradient and the poloidal flow shear determines the two-dimensional distribution of the T e turbulence. When the poloidal vortex flow forms, it can maintain the steepest T e gradient and the magnetic island acts more like an electron heat transport barrier. Interestingly, when the T e gradient, the T e turbulence, and the vortex flow shear increase beyond critical levels, the magnetic island turns into a fast electron heat transport channel, which directly leads to the minor disruption.