Spatial structure of scrape-off-layer filaments near the midplane and X-point regions of Alcator C-Mod
Movies of edge turbulence at both the outboard midplane and the region outboard of the typical lower X-point location in C-Mod have been obtained using Gas-Puff-Imaging together with fast-framing cameras. Intermittent turbulent structures, typically referred to as blobs or filaments, are observed in both locations. Near the midplane the filaments are roughly circular in cross-section, while in the X-point region they are highly elongated. Filament velocities in this region are {approx}3x faster than the radial velocities at the midplane, in a direction roughly normal to the local flux surfaces. The observations are consistent with the picture that the filaments arise in outboard region and, as a consequence of the rapid parallel diffusion of the potential perturbations, map along field lines. A simulation using the 3D BOUT turbulence code has been made, with the result that reproduces many of the spatial features observed in the experiment.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 945704
- Report Number(s):
- LLNL-CONF-404224; TRN: US0901073
- Resource Relation:
- Journal Volume: 390-391; Conference: Presented at: 18th Conference on Plasma Surface Interactions, Toledo, Spain, May 26 - May 30, 2008
- Country of Publication:
- United States
- Language:
- English
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