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Publications in Scientific Journals:

M. Cavedon, T. Pütterich, E. Viezzer, F. Laggner, A. Burckhart, M. Dunne, R. Fischer, A. Lebschy, F. Mink, U. Stroth, M. Willensdorfer, E. Wolfrum, . ASDEX Upgrade Team:
"Pedestal and Er profile evolution during an edge localized mode cycle at ASDEX Upgrade";
Plasma Physics and Controlled Fusion, 59 (2017), 10; 1050071 - 1050078.



English abstract:
The upgrade of the edge charge exchange recombination spectroscopy diagnostic at ASDEX
Upgrade has enabled highly spatially resolved measurements of the impurity ion dynamics during an
edge-localized mode cycle (ELM) with unprecedented temporal resolution, i.e. 65 μs. The increase of
transport during an ELM induces a relaxation of the ion, electron edge gradients in impurity density
and flows. Detailed characterization of the recovery of the edge temperature gradients reveals a
difference in the ion and electron channel: the maximum ion temperature gradient Ti is
re-established on similar timescales as ne, which is faster than the recovery of Te. After the
clamping of the maximum gradient, Ti and Te at the pedestal top continue to rise up to the next ELM
while ne stays constant which means that the temperature pedestal and the resulting pedestal pressure
widen until the next ELM. The edge radial electric field Er at the ELM crash is found to reduce to
typical L-mode values and its maximum recovers to its pre-ELM conditions on a similar time scale as
for ne and Ti. Within the uncertainties, the measurements of Er align with their neoclassical
predictions Er,neo for most of the ELM cycle, thus indicating that Er is dominated by collisional
processes. However, between 2 and 4ms after the ELM crash, other contributions to E B flow,
e.g. zonal flows or ion orbit effects, could not be excluded within the uncertainties.

Keywords:
edge localized mode, ion temperature, edge gradient recovery, radial electric field

Created from the Publication Database of the Vienna University of Technology.