[Zurück]

B. Vanovac, E. Wolfrum, M. Willensdorfer, M. Griener, F. Fink, G. Harrer, M. Hoelzl, . ASDEX Upgrade Team:
"Parameter space of low frequency inter-ELM modes";
in: "Proceedings 45st EPS Conference on Plasma Physics, ISBN: 979-10-96389-08-7, Prague, Czech Republic, 2 - 6 July, 2018, Europhys. Conf. Abstracts 42A", Proceedings 45st EPS Conference on Plasma Physics, 2018, ISBN: 979-10-96389-08-7, S. P2.10851 - P2.10854.

The ELM cycle of type-I ELMs consists of different phases characterized by
the evolution of kinetic profiles on different time scales [1] and distinct MHD and turbulence
activity. In the latest phase of the ELM cycle, the pressure gradients are clamped. During this
phase low [2], medium [3] and high frequency [4] MHD modes develop simultaneously in the
steep gradient region. The high-frequency modes are located close to the minimum of the Er
well, and are measured as fluctuations in the radial magnetic field on both, low and high field
side [4]. The focus of the work presented here is the low-frequency modes. The low frequency
modes are measured only at the low field side and are located further inwards, towards the
pedestal top [5]. They appear as fluctuations in the electron density, the electron temperature and
as magnetic fluctuations. These modes rotate poloidally in the electron diamagnetic direction
with the velocity of the background flow at that position [5]. The nature of this mode is not
yet clear. In this work, we show the dependences of the low-frequency mode characteristics on
some of the plasma and ELM parameters.