[Zurück]

R. Fischer, C. Fuchs, B. Kurzan, R. McDermott, T. Pütterich, S. Rathgeber, W. Suttrop, E. Viezzer, M. Willensdorfer, E. Wolfrum, . ASDEX Upgrade Team:
"Effect of non-axisymmetric magnetic perturbations on profiles at ASDEX Upgrade";
in: "Proc. 38th EPS Conference on Plasma Physics - Europhys. Conf. Abstracts", European Physical Society, 35G, 2011, ISBN: 2-914771-68-1, S. 1 - 4.

Non-axisymmetric Magnetic Perturbations (MPs) were successfully applied at ASDEX Upgrade
to substantially reduce the plasma energy loss and peak divertor power load that occur
concomitant with type-I Edge Localised Modes (ELMs) [1]. Plasmas with mitigated ELMs
show similar energy confinement, plasma density and impurity concentration as the unperturbed
reference plasmas. ELMmitigation is observed so far only above an edge density threshold. The
type-I ELMs are replaced in the mitigated phase by small-scale and high-frequency edge perturbations
(mitigated ELMs). In this paper we discuss plasma discharges that are conducted so that
three separate phases can be distinguished: A phase covering the onset of MPs, a phase where
the threshold density is reached and ELM mitigation starts, and a phase where the MPs are
switched off. Electron density ne and temperature Te profiles are determined with an Integrated
Data Analysis approach combining lithiumbeam (LIB), interferometry and ECE diagnostics [2]
and Zeff profiles [3] combining various CXRS diagnostics which also provide ion temperature
Ti, radial electric field Er, and poloidal vpol and toroidal vtor velocity profiles. The profiles are
averaged over the time intervals specified, except for the duration of type-I ELM crashes which
are removed. The mitigated ELMs are not filtered.