% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@ARTICLE{Wurden:835982,
author = {Wurden, G. A. and Biedermann, C. and Effenberg, F. and
Jakubowski, M. and Niemann, H. and Stephey, L. and
Bozhenkov, S. and Brezinsek, S. and Fellinger, J. and
Cannas, B. and Pisano, F. and Marsen, S. and Laqua, H. P.
and Harris, J. H. and Unterberg, E. A. and König, R. and
Schmitz, O.},
title = {{L}imiter observations during {W}7-{X} first plasmas},
journal = {Nuclear fusion},
volume = {57},
number = {5},
issn = {1741-4326},
address = {Vienna},
publisher = {IAEA},
reportid = {FZJ-2017-05107},
pages = {056036},
year = {2017},
abstract = {During the first operational phase (referred to as OP1.1)
of the new Wendelstein 7-X (W7-X) stellarator, five poloidal
graphite limiters were mounted on the inboard side of the
vacuum vessel, one in each of the five toroidal modules
which form the W7-X vacuum vessel. Each limiter consisted of
nine specially shaped graphite tiles, designed to conform to
the last closed field line geometry in the bean-shaped
section of the standard OP1.1 magnetic field configuration
(Sunn Pedersen et al 2015 Nucl. Fusion 55 126001). We
observed the limiters with multiple infrared and visible
camera systems, as well as filtered photomultipliers. Power
loads are calculated from infrared (IR) temperature
measurements using THEODOR, and heating patterns (dual
stripes) compare well with field line mapping and
EMC3-EIRENE predictions. While the poloidal symmetry of the
heat loads was excellent, the toroidal heating pattern
showed up to a factor of 2× variation, with peak heat
loads on Limiter 1. The total power intercepted by the
limiters was up to $~60\%$ of the input ECRH heating power.
Calorimetry using bulk tile heating (measured via post-shot
IR thermography) on Limiter 3 showed a difference between
short high power discharges, and longer lower power ones,
with regards to the fraction of energy deposited on the
limiters. Finally, fast heating transients, with
frequency >1 kHz were detected, and their visibility
was enhanced by the presence of surface coatings which
developed on the limiters by the end of the campaign.},
cin = {IEK-4},
ddc = {530},
cid = {I:(DE-Juel1)IEK-4-20101013},
pnm = {174 - Plasma-Wall-Interaction (POF3-174)},
pid = {G:(DE-HGF)POF3-174},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000398304900003},
doi = {10.1088/1741-4326/aa6609},
url = {https://juser.fz-juelich.de/record/835982},
}