Abstract
Blob properties are studied in the scrape-off layer of the tokamak ASDEX Upgrade with a fast camera. The gas-puff imaging technique is used to investigate the detection rate as well as the blob size and velocity scaling. The experiments were performed in L- and H-mode phases of the same discharges to study the change in blob properties after the L-H transition. In both regimes the detection rate is of the order of a few thousand blobs per second, which is compatible with the picture of blob generation by edge micro instabilities. The blob size increases in H-mode, while the radial velocity decreases slightly. The changes are, however, not indicating a drastic change in the blob dynamics in both phases. The experimentally found blob properties were compared to predictions from a novel blob model including effects due to a finite ion temperature, which should be more appropriate for the conditions in the SOL of fusion plasmas.
Original language | English |
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Article number | 125001 |
Journal | Plasma Physics and Controlled Fusion |
Volume | 56 |
Issue number | 12 |
DOIs | |
State | Published - 1 Dec 2014 |
Keywords
- Blobs
- Gas-puff imaging
- Plasma turbulence
- Tokamak