Characterization of edge profiles and fluctuations in discharges with type-II and nitrogen-mitigated edge localized modes in ASDEX Upgrade
SCIE
SCOPUS
- Title
- Characterization of edge profiles and fluctuations in discharges with type-II and nitrogen-mitigated edge localized modes in ASDEX Upgrade
- Authors
- Wolfrum, E; Bernert, M; Boom, JE; Burckhart, A; Classen, IGJ; Conway, GD; Eich, T; Fischer, R; Gude, A; Herrmann, A; Luhmann, NC; Maraschek, M; McDermott, R; Park, HK; Putterich, T; Vicente, J; Wiel; , B; Willensdorfer, M
- Date Issued
- 2011-08
- Publisher
- IOP PUBLISHING
- Abstract
- Edge localized modes (ELMs) with high frequency and low power loss (type-II ELMs) occur in high triangularity, near double null configurations in ASDEX Upgrade with full tungsten plasma facing components. The transition from type-I to type-II ELMs is shown to occur above a collisionality threshold. For the first time the characteristic MHD fluctuations around 40 kHz have been localized. The fluctuations are observed in a wide region extending from the pedestal inward to normalized poloidal radius rho(pol) = 0.7. Their amplitudes on the low-field side of the plasma exhibit maxima above and below the mid-plane. The fluctuations move in the electron drift direction and lead to a reduced edge electron temperature gradient. The reduction in the edge pressure gradient is connected with these MHD fluctuations, which affect the electron temperature but not the electron density profiles. A comparison with nitrogen-mitigated type-I ELMs in the same plasma shape shows that core profiles are also affected. The electron temperature profile is self-similar for type-I and nitrogen-mitigated type-I ELMs but is not self-similar in the case of type-II ELMs.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/35935
- DOI
- 10.1088/0741-3335/53/8/085026
- ISSN
- 0741-3335
- Article Type
- Article
- Citation
- Plasma Physics and Controlled Fusion, vol. 53, no. 8, page. 85026 - 85026, 2011-08
- Files in This Item:
- There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.