[Zurück]

G. Harrer, E. Wolfrum, M. Dunne, T. Eich, R. Fischer, M. Griener, P. Hennequin, A. Bock, B. Labit, P. Manz, H. Meyer, L. Radovanovic, S. Saarelma, M. Willensdorfer, F. Aumayr, . ASDEX Upgrade Team, EUROfusion MST1 Team:
"The ballooning structure of small edge localized modes in AUG and TCV";
Vortrag: 46th European Physical Society (EPS) Conference on Plasma Physics, Milan/Italy; 11.07.2019; in: "Proc. 46th EPS Conference on Plasma Physics, ISBN: 979-10-96389-11-7, Milan, Italy, 8 - 12 July, 2019, Europhys. Conf. Abstracts", (2019), S. 1 - 4.

In future fusion devices the collisionality n e µ
ne=T2
e at the pedestal top will be very low,
n e;pedtop 0:06 [1], due to the expected high temperature.
On the other hand at the very edge it
should be high, n e;sep 12, because a high separatrix
density is necessary for efficient power exhaust
[2]. These conditions cannot be reached simultaneously
in present-day machines. It is shown by the
red shaded area in figure 1, that matching the ITER
pedestal conditions in ASDEX Upgrade is only possible
at low separatrix collisionality, whilst power
exhaust experiments with high separatrix density and collisionality can only be achieved at
high n e;pedestal. This is a challenge for predictions about edge localized modes (ELMs) in ITER,
as on the one hand, a lower pedestal top collisionality is predicted to cause larger, more severe
type-I ELMs [1] and on the other hand, ASDEX Upgrade [3] and TCV [4] discharges with high
separatrix collisionality, exhibit small Edge Localized Modes. These small ELMs and the effect
of the magnetic shear on their ballooning stability, are the topic of this work.