Publications in Scientific Journals:

M. Dunne, L. Frassinetti, M. Beurskens, M. Cavedon, S. Fietz, R. Fischer, L. Giannone, G. Huijsmans, B. Kurzan, F. Laggner, P. McCarthy, R. McDermott, G. Tardini, E. Viezzer, M. Willensdorfer, E. Wolfrum, -. EUROfusion MST1 Team, . ASDEX Upgrade Team:
"Global performance enhancements via pedestal optimisation on ASDEX Upgrade";
Plasma Physics and Controlled Fusion, 59 (2017), 0250101 - 02501014.

English abstract:
Results of experimental scans of heating power, plasma shape, and nitrogen content are
presented, with a focus on global performance and pedestal alteration. In detailed scans
at low triangularity, it is shown that the increase in stored energy due to nitrogen seeding
stems from the pedestal. It is also shown that the confinement increase is driven through the
temperature pedestal at the three heating power levels studied. In a triangularity scan, an
orthogonal effect of shaping and seeding is observed, where increased plasma triangularity
increases the pedestal density, while impurity seeding (carbon and nitrogen) increases the
pedestal temperature in addition to this effect. Modelling of these effects was also undertaken,
with interpretive and predictive models being employed. The interpretive analysis shows a
general agreement of the experimental pedestals in separate power, shaping, and seeding
scans with peeling-ballooning theory. Predictive analysis was used to isolate the individual
effects, showing that the trends of additional heating power and increased triangularity can be
recoverd. However, a simple change of the effective charge in the plasma cannot explain the
observed levels of confinement improvement in the present models.

tokamak, impurity seeding, pedestal, peeling-ballooning, predictive, experiment

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