Published September 17, 2018
| Version v1
Publication
The I-mode confinement regime at ASDEX Upgrade: global propert ies and characterization of strongly intermittent density fluctuations
Description
Properties of the Imode confinement regime on the ASDEX Upgrade tokamak are
summarized. A weak dependence of the power threshold for the LI transition on the toroidal
magnetic field strength is found. During improved confinement, the edge radial electric field
well deepens. Stability calculations show that the Imode pedestal is peelingballooning stable.
Turbulence investigations reveal strongly intermittent density fluctuations linked to the weakly
coherent mode in the confined plasma, which become stronger as the confinement quality
increases. Across all investigated structure sizes (
≈
⊥
k
5
–
12 cm
−
1
, with
⊥
k
the perpendicular
wavenumber of turbulent density fluctuations), the intermittent turbulence bursts are observed.
Comparison with bolometry data shows that they move poloidally toward the Xpoint and
finally end up in the divertor. This might be indicative that they play a role in inhibiting the
density profile growth, such that no pedestal is formed in the edge density profile.
Abstract
European Union (EUROfusion 633053)Abstract
European Union (EUROfusion AWP15ENR09/IPP02)Additional details
Identifiers
- URL
- https://idus.us.es/handle//11441/78542
- URN
- urn:oai:idus.us.es:11441/78542
Origin repository
- Origin repository
- USE