Determination of the minimum value of the safety factor from geodesic Alfvén eigenmodes in Joint European Torus

A. G. Elfimov, R. M. O. Galvão, S. E. Sharapov

doi:10.1063/1.3494212

Determination of the minimum value of the safety factor from geodesic Alfvén eigenmodes in Joint European Torus

DOI PDF 被引用文献1件

A. G. Elfimov

University of São Paulo 1 Institute of Physics, , 05508-090 São Paulo, Brazil
R. M. O. Galvão

University of São Paulo 1 Institute of Physics, , 05508-090 São Paulo, Brazil
S. E. Sharapov

Culham Science Centre 3 Euratom/CCFE Fusion Association, , Abingdon OX14 3DB, United Kingdom

抄録

<jats:p>An analysis of the experimental conditions under which low-frequency (70–150 kHz) Alfvén eigenmodes (AE) are excited during the monster sawtooth in Joint European Torus [F. Romanelli et al., Proceedings of the 22nd IAEA Fusion Energy Conference, Geneva, Switzerland, 2008] is presented for the specific case of a discharge with ion cyclotron heating (5 MW). Using a simplified AE model for modes excited at the Alfvén wave continuum maximum with geodesic corrections taken into account, the temporal evolution of the value of the safety factor q0 at the magnetic axis is determined. We describe a new scheme to determine the time variation of q0 that works under conditions in which other standard diagnostics, such as the motional Stark effect do not give reliable results such as during a monster sawtooth.</jats:p>