| Title | Characterization of edge profiles and fluctuations in discharges with type-II and nitrogen-mitigated edge localized modes in ASDEX Upgrade |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | E. Wolfrum, M. Bernert, J.E Boom, A. Burckhart, I.GJ Classen, G.D Conway, T. Eich, R. Fischer, A. Gude, A. Herrmann, N.CLuhmann Jr., M. Maraschek, R. McDermott, H.K Park, T Pütterich, J. Vicente, B. Wieland, M. Willensdorfer, ASDEX Upgrade Team |
| Journal | Plasma Physics and Controlled Fusion |
| Volume | 53 |
| Issue | 8 |
| Number | 8 |
| Pagination | 085026 |
| 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 ρ 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. |
| DOI | 10.1088/0741-3335/53/8/085026 |
| Division | FP |
| Department | PDG |
| PID | 96834303cba945bc786624fc66aecfbd |
| Alternate Title | Plasma Phys. Control. Fusion |
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