2D ECE measurements of type-I edge localized modes at ASDEX Upgrade

J.E. Boom, I.G.J. Classen, P.C. de Vries, T. Eich, E. Wolfrum, W. Suttrop, R.P. Wenninger, A.J.H. Donné, B.J. Tobias, C.W. Domier, N.C. Luhmann, H.K. Park

Research output: Contribution to journalArticleAcademicpeer-review

34 Citations (Scopus)
1 Downloads (Pure)

Abstract

The installation of a 2D electron cyclotron emission imaging (ECEI) diagnostic on ASDEX Upgrade has provided a new means to observe the nature of edge localized modes (ELMs). For a series of ELMs in a typical type-I ELMy H-mode (with q95 = 4.7), the 2D dynamics have been characterized. Firstly, a clear distinction between so-called ‘fast’ and ‘slow’ ELMs was found to be the occurrence of an off-mid-plane ¿uctuation in case of the latter. This mode has its amplitude strongest off-mid-plane and its poloidal and toroidal mode numbers are m ~ 110 and n ~ 30. Secondly, prior to the onset of the ELM’s temperature collapse, a mode is observed that covers the whole ECEI-observation window. Here, the estimated poloidal and toroidal mode numbers are m ~ 75 and n ~ 20. These have been seen to increase towards the ELM crash, simultaneously with a velocity increase of the mode (in poloidal direction). Finally, ¿laments have been identi¿ed during the temperature collapse phase and their motion could be followed in the vertical direction. In contrast to both the off-mid-plane ¿uctuation and the ELM-onset mode, which only have been seen rotating in the electron diamagnetic drift direction, the ¿rst few ¿laments have sometimes been observed to move in the opposite direction as well.
Original languageEnglish
Article number103039
Pages (from-to)1-9
Number of pages9
JournalNuclear Fusion
Volume51
Issue number10
DOIs
Publication statusPublished - 2011

Fingerprint Dive into the research topics of '2D ECE measurements of type-I edge localized modes at ASDEX Upgrade'. Together they form a unique fingerprint.

Cite this