Ion temperature and toroidal velocity edge transport barriers in KSTAR. (6th July 2015)

• Record Type: Journal Article
• Authors: Ko, Won-Ha; Ko, S.H.; Kwon, J.M.; Diamond, P.H.; Ida, K.; Jeon, Y.M.; Lee, J.H.; Yoon, S.W.; Kwak, J.G.
• Is Part Of: Nuclear fusion. Volume 55:Number 8(2015:Aug.)
• Publication Date: 2015-07-06
• Subjects: toroidal rotation pedestal -- ion temperature pedestal -- gyrokinetic stability -- RMPs -- KSTAR -- charge exchange spectroscopy; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/55/8/083013
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: The structure and evolution of the ion temperature ( ) and toroidal rotation ( ) profile have been investigated in neutral beam injection (NBI)-heated KSTAR H-mode plasmas, both without and with resonant magnetic pertubations (RMPs). A clear disparity between the width of the -pedestal and that of the -pedestal was observed. Also, it was found that there exists a close correlation and weak relative hysteresis between the pedestal and during both L → H and H → L transitions. During the L → H transition, the -pedestal is observed to form ahead of the -pedestal, and build inward from the separatrix. Linear gyrokinetic stability analysis of these KSTAR profiles was performed. The results indicate that parallel velocity shear is a relevant drive for pedestal turbulence and transport. This was largely ignored in previous studies of the pedestal micro-stability. Pedestal ion temperature and rotation profiles were also measured during edge localized mode (ELM) suppression experiments on KSTAR using an n = 1 RMPs. It was found that the top values of the ion temperature and toroidal rotation pedestal drop with RMPs when ELMs are suppressed.