Alfven mode stability and wave-particle interaction in the JET tokamak: prospects for scenario development and control schemes in burning plasma experiments
2004 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 46, no 7, S59-S79 p.Article in journal (Refereed) Published
We have investigated the effect of different ion cyclotron resonance frequency (ICRF) heating schemes, of error field modes, of the plasma shape and edge magnetic shear, and of the ion delB drift direction on the stability of Alfven eigenmodes (AEs). The use of multi-frequency or 2nd harmonic minority ICRF heating at high plasma density gives rise to a lower fast ion pressure gradient in the plasma core and to a reduced mode activity in the Alfven frequency range. Externally excited low-amplitude error fields lead to a much larger AE instability threshold, which we attribute to a moderate radial redistribution of the fast ions. The edge plasma shape has a clear stabilizing effect on high-n, radially localized AEs. The damping rate of n = 1 toroidal AEs is a factor 3 higher when the ion VB drift is directed towards the divertor. These results represent a useful step towards the extrapolation of current scenarios to the inclusion of fusion-born alpha particles in ITER, with possible application for feedback control schemes for the various ITER operating regimes.
Place, publisher, year, edition, pages
2004. Vol. 46, no 7, S59-S79 p.
joint european torus, deuterium plasmas, eigenmodes, confinement, rotation, regime, icrf, impurity, shear
IdentifiersURN: urn:nbn:se:kth:diva-23631DOI: 10.1088/0741-3335/46/7/S05ISI: 000223135400006ScopusID: 2-s2.0-3242679120OAI: oai:DiVA.org:kth-23631DiVA: diva2:342330
QC 20100525 QC 20111018. 8th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems. Unic Calif Irvine, Irvine, CA. OCT 06-08, 2003 2010-08-102010-08-102011-10-18Bibliographically approved