Modelling of (2,1) NTM threshold in JET advanced scenarios

P. Maget, H. Lütjens, R. Coelho, B. Alper, M. Brix, P. Buratti, R.J. Buttery, E. De La Luna, N. Hawkes, G.T.A. Huysmans, I. Jenkins, C.D. Challis, C. Giroud, X. Litaudon, J. Mailloux, M. Ottaviani

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Abstract

The limit to high performances advanced scenario discharges with qminabove unity is generally set by the (2,1) magneto-hydro-dynamic (MHD) mode in JET. We investigate here the possibility that this mode is a (2,1) neoclassical tearing mode (NTM) by computing the critical island width at which such mode would be unstable, using a non-linear MHD code where the relevant bootstrap current physics is accounted for. We show that the triggering of a (2,1) NTM is consistent with a lowering of the critical island width as the plasma current diffuses towards the centre. This is explained partly by the increase in the magnetic shear at the resonant surface, which weakens the curvature stabilization term, as found in the analytical framework of a generalized Rutherford equation. A comparison with experiment is made in the non-linear regime, showing encouraging results on the dynamics of the confinement degradation and mode structure. © 2010 IAEA, Vienna.
Original languageEnglish
Article number045004
Pages (from-to)-
JournalNuclear Fusion
Volume50
Issue number4
DOIs
Publication statusPublished - 2010
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Maget, P., Lütjens, H., Coelho, R., Alper, B., Brix, M., Buratti, P., ... Ottaviani, M. (2010). Modelling of (2,1) NTM threshold in JET advanced scenarios. Nuclear Fusion, 50(4), -. [045004]. https://doi.org/10.1088/0029-5515/50/4/045004