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

Technical Report · Mon Nov 22 04:00:00 EST 2010

DOI:https://doi.org/10.2172/1001663· OSTI ID:1001663

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.

• Research Organization: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• OSTI ID: 1001663
• Report Number(s): PPPL-4574
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM INJECTION
CONFINEMENT
EMISSION
Edge Plasma
Scrape-off Layer (SOL
Transport Phenomena
Tokamaks
NSTX
FLUCTUATIONS
INHIBITION
LAYERS
LEVELS
POWER
SOLS
TURBULENCE
USES