Speaker
Dr
David Hatch
(Institute for Fusion Studies, University of Texas at Austin)
Description
The gyrokinetic Gene code is used to study Inter-ELM H-mode pedestal profile evolu- tion for an ASDEX-Upgrade discharge. Four main instabilities are observed during various inter-ELM phases—density gradient driven drift waves (DW), microtearing modes (MTM), kinetic ballooning modes (KBM), and electron temperature gradient (ETG) modes. DWs are the dominant pedestal instability during the early density-buildup phase. The drift waves are characterized by significant outward particle flux, and show no evidence of a large pinch mechanism. The electron temperature gradient achieves a critical value early in the ELM cycle, concurrent with the appearance of both MTMs and ETG modes. The nom- inal profiles are stable to KBMs, but moderate increases in β are sufficient to surpass the KBM threshold. Certain aspects of the dynamics support the premise of KBM-constrained pedestal evolution; the density and temperature profiles separately undergo large changes, but in a manner which keeps the pressure profile constant and near the KBM limit. Non- linear simulations of DW turbulence and ETG turbulence are also described.
| Country or International Organisation | USA |
|---|---|
| Paper Number | PD/P5-4 |
Primary author
Dr
David Hatch
(Institute for Fusion Studies, University of Texas at Austin)
Co-authors
Dr
Daniel Told
(IPP-Garching)
Dr
Eleonora Viezzer
(Max-Planck-Institut fuer Plasmaphysik)
Dr
Elisabeth Wolfrum
(Max Planck Institut fuer Plasmaphysik)
Prof.
Frank Jenko
(Max Planck Institute for Plasma Physics)
Dr
Hauke Doerk
(IPP-Garching)
M.J. Pueschel
(University of Wisconsin-Madison)
Dr
Mike Dunne
(IPP-Garching)
