Effect of q-profile modification by LHCD on internal transport barriers in JET

C.D. Challis, Yu.F. Baranov, G.D. Conway, C. Gormezano, C.W. Gowers, N.C. Hawkes, T.C. Hender, E. Joffrin, J. Mailloux, D. Mazon, S. Podda, R. Prentice, F.G. Rimini, S.E. Sharapov, A.C.C. Sips, B.C. Stratton, D. Testa, K.-D. Zastrow

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Optimized shear (OS) experiments in JET can generate an internal transport barrier (ITB) during a high power heating phase early in the plasma discharge. A strong link is generally observed between the formation of the barrier and the location of an integer q magnetic surface within a low magnetic shear (s = r/q(dq/dr)) region of the plasma. However, if the q-profile for such experiments is modified by applying lower hybrid heating and current drive (LHCD) before the main heating pulse, to provide a region of reduced or negative magnetic shear in the plasma core, ITBs can be formed the location of which does not exhibit any apparent association with a particular internal magnetic surface. Initial results suggest that q-profile modification using an LHCD prelude can also be used to reduce the heating power level required for ITB generation.
Original languageEnglish
Pages (from-to)861 - 879
Number of pages19
JournalPlasma Physics and Controlled Fusion
Issue number7
Publication statusPublished - Jul 2001
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Condensed Matter Physics

Cite this

Challis, C. D., Baranov, Y. F., Conway, G. D., Gormezano, C., Gowers, C. W., Hawkes, N. C., ... Zastrow, K-D. (2001). Effect of q-profile modification by LHCD on internal transport barriers in JET. Plasma Physics and Controlled Fusion, 43(7), 861 - 879. https://doi.org/10.1088/0741-3335/43/7/303