Prepared for the U . S . Department of Energy under Contract DE - AC 02 - 09 CH 11466 . Princeton Plasma

Abstract

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. JNM

4 Figures and Tables

Cite this paper

@inproceedings{Maqueda2008PreparedFT, title={Prepared for the U . S . Department of Energy under Contract DE - AC 02 - 09 CH 11466 . Princeton Plasma}, author={R . J . Maqueda and D P Stotler and S J Zweben}, year={2008} }