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Publications in Scientific Journals:

F. Laggner, E. Wolfrum, M. Cavedon, F. Mink, E. Viezzer, M. Dunne, P. Manz, H. Doerk, G. Birkenmeier, R. Fischer, S. Fietz, M. Maraschek, M. Willensdorfer, F. Aumayr, -. EUROfusion MST1 Team, . ASDEX Upgrade Team:
"High frequency magnetic fluctuations correlated with the inter-ELM pedestal evolution in ASDEX Upgrade";
Plasma Phys. Control. Fusion, 58 (2016), 0650051 - 0650058.



English abstract:
In order to understand the mechanisms that determine the structure of the high confinement
mode (H-mode) pedestal, the evolution of the plasma edge electron density and temperature
profiles between edge localised modes (ELMs) is investigated. The onset of radial magnetic
fluctuations with frequencies above 200 kHz is found to correlate with the stagnation of the
electron temperature pedestal gradient. During the presence of these magnetic fluctuations
the gradients of the edge electron density and temperature are clamped and stable against the
ELM onset. The detected magnetic fluctuation frequency is analysed for a variety of plasma
discharges with different electron pressure pedestals. It is shown that the magnetic fluctuation
frequency scales with the neoclassically estimated EB velocity at the plasma edge. This
points to a location of the underlying instability in the gradient region. Furthermore, the
magnetic signature of these fluctuations indicates a global mode structure with toroidal mode
numbers of approximately 10. The fluctuations are also observed on the high field side with
significant amplitude, indicating a mode structure that is symmetric on the low field side
and high field side. The associated fluctuations in the current on the high field side might be
attributed to either a strong peeling part or the presence of non-adiabatic electron response.

Keywords:
plasma, tokamak, H-mode, edge localised modes, profile

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