Ubiquity of non-diffusive momentum transport in JET H-modes

JET-EFDA collaborators

    Research output: Contribution to journalArticleScientificpeer-review

    10 Citations (Scopus)

    Abstract

    A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the normalized angular frequency gradient R∇ω/ω is higher than expected from momentum diffusion alone, by about unity in the core (r/a ~ 0.3), rising to near 5 close to the edge, where its contribution to the total gradient is comparable to the gradient associated with the diffusive flux. The magnitude and parameter dependences of the non-diffusive contribution to the gradient are consistent with a theoretically expected pinch, which has its origin in the vertical particle drift resulting from the Coriolis force. Linear gyrokinetic calculations of the pinch number RV/χphiv and the Prandtl number χphiv/χi are in good agreement with the experimental observations, with similar dependences on R/Ln, q and ε = r/R. A contribution due to residual stresses may also be present, but could not be identified with certainty.
    Original languageEnglish
    Article number114024
    JournalNuclear Fusion
    Volume52
    Issue number11
    DOIs
    Publication statusPublished - 2012
    MoE publication typeA1 Journal article-refereed

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    momentum
    gradients
    rotating plasmas
    neutral beams
    Prandtl number
    residual stress
    unity

    Cite this

    JET-EFDA collaborators. / Ubiquity of non-diffusive momentum transport in JET H-modes. In: Nuclear Fusion. 2012 ; Vol. 52, No. 11.
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    title = "Ubiquity of non-diffusive momentum transport in JET H-modes",
    abstract = "A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the normalized angular frequency gradient R∇ω/ω is higher than expected from momentum diffusion alone, by about unity in the core (r/a ~ 0.3), rising to near 5 close to the edge, where its contribution to the total gradient is comparable to the gradient associated with the diffusive flux. The magnitude and parameter dependences of the non-diffusive contribution to the gradient are consistent with a theoretically expected pinch, which has its origin in the vertical particle drift resulting from the Coriolis force. Linear gyrokinetic calculations of the pinch number RV/χphiv and the Prandtl number χphiv/χi are in good agreement with the experimental observations, with similar dependences on R/Ln, q and ε = r/R. A contribution due to residual stresses may also be present, but could not be identified with certainty.",
    author = "H. Weisen and Y. Camanen and A. Salmi and T.W. Versloot and P.C. Devries and M. Maslov and Tuomas Tala and M. Beurskens and C. Giroud and {JET-EFDA collaborators}",
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    language = "English",
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    Ubiquity of non-diffusive momentum transport in JET H-modes. / JET-EFDA collaborators.

    In: Nuclear Fusion, Vol. 52, No. 11, 114024, 2012.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Ubiquity of non-diffusive momentum transport in JET H-modes

    AU - Weisen, H.

    AU - Camanen, Y.

    AU - Salmi, A.

    AU - Versloot, T.W.

    AU - Devries, P.C.

    AU - Maslov, M.

    AU - Tala, Tuomas

    AU - Beurskens, M.

    AU - Giroud, C.

    AU - JET-EFDA collaborators

    PY - 2012

    Y1 - 2012

    N2 - A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the normalized angular frequency gradient R∇ω/ω is higher than expected from momentum diffusion alone, by about unity in the core (r/a ~ 0.3), rising to near 5 close to the edge, where its contribution to the total gradient is comparable to the gradient associated with the diffusive flux. The magnitude and parameter dependences of the non-diffusive contribution to the gradient are consistent with a theoretically expected pinch, which has its origin in the vertical particle drift resulting from the Coriolis force. Linear gyrokinetic calculations of the pinch number RV/χphiv and the Prandtl number χphiv/χi are in good agreement with the experimental observations, with similar dependences on R/Ln, q and ε = r/R. A contribution due to residual stresses may also be present, but could not be identified with certainty.

    AB - A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the normalized angular frequency gradient R∇ω/ω is higher than expected from momentum diffusion alone, by about unity in the core (r/a ~ 0.3), rising to near 5 close to the edge, where its contribution to the total gradient is comparable to the gradient associated with the diffusive flux. The magnitude and parameter dependences of the non-diffusive contribution to the gradient are consistent with a theoretically expected pinch, which has its origin in the vertical particle drift resulting from the Coriolis force. Linear gyrokinetic calculations of the pinch number RV/χphiv and the Prandtl number χphiv/χi are in good agreement with the experimental observations, with similar dependences on R/Ln, q and ε = r/R. A contribution due to residual stresses may also be present, but could not be identified with certainty.

    U2 - 10.1088/0029-5515/52/11/114024

    DO - 10.1088/0029-5515/52/11/114024

    M3 - Article

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    JO - Nuclear Fusion

    JF - Nuclear Fusion

    SN - 0029-5515

    IS - 11

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