Speaker
Alexander Felician Mink
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1015.pdf
Scaling of ELM Crash Parameters
A.F. Mink1,2 , E. Wolfrum1 , M. Hoelzl1 , M. Maraschek1 , B. Vanovac1,3 , G.F. Harrer1,4 ,
M. Cavedon1 , E. Trier1 , A. Cathey1 , U. Stroth1,2 and the ASDEX Upgrade team
1 Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching, Germany
2 Physik Department, E28, TUM, 85748 Garching, Germany
3 DIFFER — Dutch Institute for Fundamental Energy Research, Eindhoven, the Netherlands
4 Institute of Applied Physics, TU Wien, Fusion@ÖAW, 1040 Vienna, Austria
In the pedestal region, which is characterized by steep pressure gradients, mode structures
are observed during crashes of edge localized modes (ELMs) and in the phase between them.
Recent observations showed that the crash phases are dominated by low toroidal mode numbers
(n = 1–7) on the ASDEX Upgrade tokamak, which fits to comparisons to the nonlinear magne-
tohydrodynamic code JOREK [1]. In order to understand the dominant physical mechanisms,
the comparison of modeling and experiment for cases with a significant variation of critical
parameters is essential.
A parameter scaling conducted on ASDEX Up-
grade shows that the toroidal mode numbers of
ELM crashes increase with decreasing the edge
safety factor q95 , see figure 1. Other peeling-
ballooning relevant parameters such as bootstrap
current, normalized pressure gradient or triangular-
ity do not show a clear trend. In addition to that it
is shown that the ELM duration and intensity also
varies with q95 , which is in line with previous stud-
ies on different machines [2, 3]. Figure 1: Average toroidal mode numbers hni
of mode structures during the ELM crashes
Starting from the results of the ASDEX Upgrade of 30 ASDEX Upgrade H-mode discharges
parameter scaling an intuitive geometric model is against the edge safety factor q95 .
presented that can explain the q95 scaling of the
toroidal structure by the dominance of one poloidal structure. Furthermore, experimental scal-
ings are compared to modelling results from advanced JOREK simulations [4].
References
[1] A. F. Mink et al., Nuclear Fusion, 58, 2 (2018)
[2] L. Frassinetti et al., Nuclear Fusion, 55, 2 (2015)
[3] T. Eich et al., Nuclear Materials and Energy, 12, 84–90 (2017)
[4] M. Hoelzl et al., Contributions to Plasma Physics, accepted (2018).
