Kiel 2004 – wissenschaftliches Programm
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P: Plasmaphysik
P 5: Magnetischer Einschluss I
P 5.3: Fachvortrag
Dienstag, 9. März 2004, 11:30–11:50, H\"orsaal D
NTM Control via Sawtooth Tailoring in ASDEX Upgrade — •Anja Mueck1, Timothy Goodman2, Marc Maraschek1, François Ryter1, Hartmut Zohm1, and ASDEX Ugrade Team1 — 1MPI für Plasmaphysik, D-85748 Garching, Germany, EURATOM-Ass. — 2CRPP EPFL, Association Euratom, CH-1015 Lausanne
In hot fusion plasmas, core magnetohydrodynamic modes like the so-called sawtooth instability can occur. During a sawtooth crash, a slow rise in plasma temperature is followed by a rapid crash. In the crash phase, the hot plasma center is thrown out into colder outer plasma regions. The control of the sawtooth instability is of great relevance for future reactor-grade devices such as ITER. Besides the influence on the fusion power output, the stabilizing effect of α-particles, created in D-T fusion processes, is expected to lead to sawtooth stabilization. The sawteeth connected with long sawtooth periods might act as a trigger for another instability, the so-called neoclassical tearing modes (NTMs). NTMs lead to a limit in the plasma beta, a value measuring the plasma pressure normalized to the magnetic field pressure.
The influence of the injection geometry of neutral beam heating on the sawtooth period will be discussed as well as sawtooth control by local electron cyclotron resonance heating and current drive. In ASDEX Upgrade, the prevention of triggering NTMs and possible increase in beta, as has been indicated in JET, will be presented.