Characterization of core microturbulence in L-mode and H-mode regimes on the EAST superconducting tokamak. (21st January 2015)

• Record Type: Journal Article
• Authors: Cao, G M; Li, Y D; Li, Q; Zhang, X D; Sun, P J; Wu, G J; Hu, L Q
• Other Names: collab.
• Is Part Of: Physica scripta. Volume 90:Number 2(2015:Feb.)
• Publication Date: 2015-01-21
• Subjects: core microturbulence -- collective scattering -- H-mode; 52.25.Fi -- 52.25.Gj -- 52.55.Fa -- 52.35.Ra; Physics -- Periodicals; 530.05
• DOI: 10.1088/0031-8949/90/2/025603
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: The core microturbulence (, ) provided by a tangential CO2 laser collective scattering system on the EAST tokamak, in low (L) and high (H) confinement mode regimes respectively, are presented. We report the change of core microturbulence characteristics from L-mode to H-mode: firstly, the spectrograms of the core microturbulence show the redistribution of microturbulence in the frequency domain after the L–H transition; secondly, the time evolution of the integrated spectral power displays that the amplitude of the core microturbulence in H-mode is much larger than that in L-mode; thirdly, the cross-correlation time-frequency spectrum analysis indicates that the structural characteristics of the core microturbulence in L-mode and H-mode are very different. These results suggest that both the amplitude and the structural characteristics of the core microturbulence change significantly from L-mode to H-mode, although the spatial extent of the transport barrier in H-mode is at the edge, which could be closely related to the changes of the profiles of basic plasma parameters.