Intermittency in the Scrape-off Layer of the National Spherical Torus Experiment During H-mode Confinement

Maqueda, R. J. ; Stotler, D. P. ; Zweben, S. J. ; National Spherical Torus Experiment (Project)

Princeton University. Plasma Physics Laboratory.

关键词: Beam Injection;    Power;    Layers;    70 Plasma Physics And Fusion Technology;    Edge Plasma, Scrape-Off Layer (Sol, Transport Phenomena, Tokamaks, Nstx;   

DOI  :  10.2172/1001663
RP-ID  :  PPPL-4574
RP-ID  :  DE-ACO2-09CH11466
RP-ID  :  1001663

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来源: UNT Digital Library

【 摘 要 】

A gas puff imaging diagnostic is used in the National Spherical Tokamak Experiment [M. Ono, et al., Nucl. Fusion 40, 557 (2000)] to study the edge turbulence and intermittency present during H-mode discharges. In the case of low power Ohmic H-modes the suppression of turbulence/blobs is maintained through the duration of the (short lived) H-modes. Similar quiescent edges are seen during the early stages of H-modes created with the use of neutral beam injection. Nevertheless, as time progresses following the L-H transition, turbulence and blobs reappear although at a lower level than that typically seen during L-mode confinement. It is also seen that the time-averaged SOL emission profile broadens, as the power loss across the separatrix increases. These broad profiles are characterized by a large level of fluctuations and intermittent events.