Parametric dependences of momentum pinch and Prandtl number in JET

JET-EFDA collaborators

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    24 Citations (Scopus)

    Abstract

    Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate 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 -Rvpinch / χφ = 1.2R/Ln + 1.4. There is no dependence of the pinch number on collisionality, whereas the pinch seems to depend weakly on q-profile, the pinch number decreasing with increasing q. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyro-kinetic 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, in particular in L-mode plasmas. The extrapolation of these results to ITER illustrates that at large enough 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
    Article number123002
    Number of pages11
    JournalNuclear Fusion
    Volume51
    Issue number12
    DOIs
    Publication statusPublished - 2011
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Prandtl number
    momentum
    extrapolation
    braking
    beam injection
    simulation
    neutral beams
    kinetics
    profiles
    torque
    modulation
    scaling
    gradients

    Cite this

    JET-EFDA collaborators. / Parametric dependences of momentum pinch and Prandtl number in JET. In: Nuclear Fusion. 2011 ; Vol. 51, No. 12.
    @article{7ac45b30b64a47638818fededb165659,
    title = "Parametric dependences of momentum pinch and Prandtl number in JET",
    abstract = "Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate 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 -Rvpinch / χφ = 1.2R/Ln + 1.4. There is no dependence of the pinch number on collisionality, whereas the pinch seems to depend weakly on q-profile, the pinch number decreasing with increasing q. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyro-kinetic 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, in particular in L-mode plasmas. The extrapolation of these results to ITER illustrates that at large enough 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.",
    author = "Tuomas Tala and Antti Salmi and C. Angioni and F.J. Casson and G Corrigan and J. Ferreira and C Giroud and P. Mantica and V. Naulin and Peeters, {A. G.} and W.M. Solomon and D. Strintzi and M. Tsalas and Versloot, {T. W.} and K.-D. Zastrow and {JET-EFDA collaborators}",
    year = "2011",
    doi = "10.1088/0029-5515/51/12/123002",
    language = "English",
    volume = "51",
    journal = "Nuclear Fusion",
    issn = "0029-5515",
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    }

    Parametric dependences of momentum pinch and Prandtl number in JET. / JET-EFDA collaborators.

    In: Nuclear Fusion, Vol. 51, No. 12, 123002, 2011.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Parametric dependences of momentum pinch and Prandtl number in JET

    AU - Tala, Tuomas

    AU - Salmi, Antti

    AU - Angioni, C.

    AU - Casson, F.J.

    AU - Corrigan, G

    AU - Ferreira, J.

    AU - Giroud, C

    AU - Mantica, P.

    AU - Naulin, V.

    AU - Peeters, A. G.

    AU - Solomon, W.M.

    AU - Strintzi, D.

    AU - Tsalas, M.

    AU - Versloot, T. W.

    AU - Zastrow, K.-D.

    AU - JET-EFDA collaborators

    PY - 2011

    Y1 - 2011

    N2 - Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate 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 -Rvpinch / χφ = 1.2R/Ln + 1.4. There is no dependence of the pinch number on collisionality, whereas the pinch seems to depend weakly on q-profile, the pinch number decreasing with increasing q. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyro-kinetic 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, in particular in L-mode plasmas. The extrapolation of these results to ITER illustrates that at large enough 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.

    AB - Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate 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 -Rvpinch / χφ = 1.2R/Ln + 1.4. There is no dependence of the pinch number on collisionality, whereas the pinch seems to depend weakly on q-profile, the pinch number decreasing with increasing q. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyro-kinetic 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, in particular in L-mode plasmas. The extrapolation of these results to ITER illustrates that at large enough 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.

    U2 - 10.1088/0029-5515/51/12/123002

    DO - 10.1088/0029-5515/51/12/123002

    M3 - Article

    VL - 51

    JO - Nuclear Fusion

    JF - Nuclear Fusion

    SN - 0029-5515

    IS - 12

    M1 - 123002

    ER -