Poloidal asymmetric flow and current relaxation of ballooned transport during I-phase in ASDEX Upgrade
P. Manz, G. Birkenmeier, G. Fuchert, M. Cavedon, G. D. Conway, M. Maraschek, A. Medvedeva, F. Mink, B. D. Scott, L. M. Shao, U. Stroth, ASDEX Upgrade Team
Abstract
Turbulence driven poloidal asymmetric parallel flow and current perturbations are studied for tokamak plasmas of circular geometry. Whereas zonal flows can lead to in-out asymmetry of parallel flows and currents via the Pfirsch–Schlüter mechanism, ballooned transport can result in an up-down asymmetry due to the Stringer spin-up mechanism. Measurements of up-down asymmetric parallel current fluctuations occurring during the I-phase in ASDEX Upgrade are not responses to the equilibrium by the Pfirsch–Schlüter current, but can be interpreted as a response to strongly ballooned plasma transport coupled with the Stringer spin-up mechanism. A good agreement of the experimental measured limit-cycle frequencies during I-phase with the Stringer spin-up relaxation frequency is found.
BibTeX
@article{Manz_2016,
title={Poloidal asymmetric flow and current relaxation of ballooned transport during I-phase in ASDEX Upgrade},
volume={23},
ISSN={1089-7674},
url={http://dx.doi.org/10.1063/1.4948787},
DOI={10.1063/1.4948787},
number={5},
journal={Physics of Plasmas},
publisher={AIP Publishing},
author={Manz, P. and Birkenmeier, G. and Fuchert, G. and Cavedon, M. and Conway, G. D. and Maraschek, M. and Medvedeva, A. and Mink, F. and Scott, B. D. and Shao, L. M. and Stroth, U. and },
year={2016},
month=May }