NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET

Tuomas Tala, Antti Salmi, P. Mantica, C. Angioni, G Corrigan, P.C. de Vries, C. Giroud, J. Ferreira, J. Lönnroth, V. Naulin, A.G. Peeters, W. Solomon, D. Strintzi, M. Tsalas, T.W. Versloot, J. Weiland, K.-D. Zastrow, JET-EFDA contributors

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


    Several parametric scans have been performed to study momentum transport on JET. NBI modulation technique has been applied to separating the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density gradient length, with an experimental scaling for the pinch number being $-Rv_{pinch}/\chi\phi = 1.2R/L_n + 1.4$. There is no dependence of the pinch number on collisionality. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyrokinetic simulations show qualitatively similar dependence of the pinch number on R/Ln, but the dependence is weaker in the simulations. Gyro-kinetic simulations do not find any clear parametric dependence in the Prandtl number, in agreement with experiments, but the experimental values are larger than the simulated ones. The extrapolation of these results to ITER illustrates that at R/Ln>2 the pinch number becomes large enough (> 3-4) to make the rotation profile peaked provided that the edge rotation is non-zero. And this rotation peaking can be achieved with small or even with no core torque source. The absolute value of the core rotation is still very challenging to predict partly due to the lack of the present knowledge of the rotation at the plasma edge, partly due to insufficient understanding of 3D effects like braking and partly due to the uncertainties in the extrapolation of the present momentum transport results to a larger device.
    Original languageEnglish
    Title of host publicationProceedings
    Subtitle of host publication38th EPS Conference on Plasma Physics, EPS 2011
    EditorsA. Becoulet
    PublisherEuropean Physical Society
    ISBN (Print)2-914771-68-1, 978-1-6183-9593-1
    Publication statusPublished - 2011
    MoE publication typeA4 Article in a conference publication
    Event38th EPS Conference on Plasma Physics - Strasbourg, France
    Duration: 27 Jun 20111 Jul 2011


    Conference38th EPS Conference on Plasma Physics
    Abbreviated titleEPS 2011


    • plasma physics


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