Toroidal and poloidal momentum transport studies in tokamaks

Tuomas Tala (Corresponding Author), K. Crombe, P.C. De Vries, J. Ferreira, P. Mantica, A.G. Peeters, Y. Andrew, R. Budny, G. Corrigan, A. Eriksson, X. Garbet, C. Giroud, M.-D. Hua, H. Nordman, V. Naulin, M.F.F. Nave, V. Parail, Karin Rantamäki, B.D. Scott, P. StrandG. Tardini, A. Thyagaraja, J. Weiland, K.-D. Zastrow

    Research output: Contribution to journalArticleScientificpeer-review

    48 Citations (Scopus)

    Abstract

    The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper.
    Similar energy confinement and momentum confinement times, i.e. τE/τphgr ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity χphgreff/χi,eff among different tokamaks can be found.
    For example, the value of effective Prandtl number is typically around χphgreff/χi,eff ≈ 0.2 on JET while still τE/τphgr ≈ 1 holds.
    Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number χphgr/χi of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation.
    The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E × B flow shear and hence modify and can significantly improve the simulation predictions.

    Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also the Weiland model predict the existence of an anomalous poloidal velocity, peaking in the vicinity of the ITB and driven dominantly by the flow due to the Reynold's stress.
    It is worth noting that these codes and models treat the equilibrium in a simplified way and this affects the geodesic curvature effects and geodesic acoustic modes.
    The neo-classical equilibrium is calculated more accurately in the GEM code and the simulations suggest that the spin-up of poloidal velocity is a consequence of the plasma profiles steepening when the ITB grows, following in particular the growth of the toroidal velocity within the ITB.
    Original languageEnglish
    Pages (from-to)B291-B302
    JournalPlasma Physics and Controlled Fusion
    Volume49
    Issue number12B
    DOIs
    Publication statusPublished - 2007
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Momentum
    momentum
    Prandtl number
    Plasmas
    diffusivity
    Turbulence
    simulation
    turbulence
    Air cushion vehicles
    Reynolds stress
    Phase behavior
    Shear flow
    shear flow
    curvature
    Electric fields
    Modulation
    modulation
    perturbation
    heat
    Kinetics

    Keywords

    • JET
    • plasma toroidal confinement
    • toroidal momentum transport
    • Tokamak
    • ITER
    • fusion energy
    • fusion reactors
    • plasma

    Cite this

    Tala, T., Crombe, K., De Vries, P. C., Ferreira, J., Mantica, P., Peeters, A. G., ... Zastrow, K-D. (2007). Toroidal and poloidal momentum transport studies in tokamaks. Plasma Physics and Controlled Fusion, 49(12B), B291-B302. https://doi.org/10.1088/0741-3335/49/12B/S27
    Tala, Tuomas ; Crombe, K. ; De Vries, P.C. ; Ferreira, J. ; Mantica, P. ; Peeters, A.G. ; Andrew, Y. ; Budny, R. ; Corrigan, G. ; Eriksson, A. ; Garbet, X. ; Giroud, C. ; Hua, M.-D. ; Nordman, H. ; Naulin, V. ; Nave, M.F.F. ; Parail, V. ; Rantamäki, Karin ; Scott, B.D. ; Strand, P. ; Tardini, G. ; Thyagaraja, A. ; Weiland, J. ; Zastrow, K.-D. / Toroidal and poloidal momentum transport studies in tokamaks. In: Plasma Physics and Controlled Fusion. 2007 ; Vol. 49, No. 12B. pp. B291-B302.
    @article{602ce72fa79f410b982c58cce3b9e4c7,
    title = "Toroidal and poloidal momentum transport studies in tokamaks",
    abstract = "The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. τE/τphgr ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity χphgreff/χi,eff among different tokamaks can be found. For example, the value of effective Prandtl number is typically around χphgreff/χi,eff ≈ 0.2 on JET while still τE/τphgr ≈ 1 holds. Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number χphgr/χi of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation. The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E × B flow shear and hence modify and can significantly improve the simulation predictions. Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also the Weiland model predict the existence of an anomalous poloidal velocity, peaking in the vicinity of the ITB and driven dominantly by the flow due to the Reynold's stress. It is worth noting that these codes and models treat the equilibrium in a simplified way and this affects the geodesic curvature effects and geodesic acoustic modes. The neo-classical equilibrium is calculated more accurately in the GEM code and the simulations suggest that the spin-up of poloidal velocity is a consequence of the plasma profiles steepening when the ITB grows, following in particular the growth of the toroidal velocity within the ITB.",
    keywords = "JET, plasma toroidal confinement, toroidal momentum transport, Tokamak, ITER, fusion energy, fusion reactors, plasma",
    author = "Tuomas Tala and K. Crombe and {De Vries}, P.C. and J. Ferreira and P. Mantica and A.G. Peeters and Y. Andrew and R. Budny and G. Corrigan and A. Eriksson and X. Garbet and C. Giroud and M.-D. Hua and H. Nordman and V. Naulin and M.F.F. Nave and V. Parail and Karin Rantam{\"a}ki and B.D. Scott and P. Strand and G. Tardini and A. Thyagaraja and J. Weiland and K.-D. Zastrow",
    year = "2007",
    doi = "10.1088/0741-3335/49/12B/S27",
    language = "English",
    volume = "49",
    pages = "B291--B302",
    journal = "Plasma Physics and Controlled Fusion",
    issn = "0741-3335",
    publisher = "Institute of Physics IOP",
    number = "12B",

    }

    Tala, T, Crombe, K, De Vries, PC, Ferreira, J, Mantica, P, Peeters, AG, Andrew, Y, Budny, R, Corrigan, G, Eriksson, A, Garbet, X, Giroud, C, Hua, M-D, Nordman, H, Naulin, V, Nave, MFF, Parail, V, Rantamäki, K, Scott, BD, Strand, P, Tardini, G, Thyagaraja, A, Weiland, J & Zastrow, K-D 2007, 'Toroidal and poloidal momentum transport studies in tokamaks', Plasma Physics and Controlled Fusion, vol. 49, no. 12B, pp. B291-B302. https://doi.org/10.1088/0741-3335/49/12B/S27

    Toroidal and poloidal momentum transport studies in tokamaks. / Tala, Tuomas (Corresponding Author); Crombe, K.; De Vries, P.C.; Ferreira, J.; Mantica, P.; Peeters, A.G.; Andrew, Y.; Budny, R.; Corrigan, G.; Eriksson, A.; Garbet, X.; Giroud, C.; Hua, M.-D.; Nordman, H.; Naulin, V.; Nave, M.F.F.; Parail, V.; Rantamäki, Karin; Scott, B.D.; Strand, P.; Tardini, G.; Thyagaraja, A.; Weiland, J.; Zastrow, K.-D.

    In: Plasma Physics and Controlled Fusion, Vol. 49, No. 12B, 2007, p. B291-B302.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Toroidal and poloidal momentum transport studies in tokamaks

    AU - Tala, Tuomas

    AU - Crombe, K.

    AU - De Vries, P.C.

    AU - Ferreira, J.

    AU - Mantica, P.

    AU - Peeters, A.G.

    AU - Andrew, Y.

    AU - Budny, R.

    AU - Corrigan, G.

    AU - Eriksson, A.

    AU - Garbet, X.

    AU - Giroud, C.

    AU - Hua, M.-D.

    AU - Nordman, H.

    AU - Naulin, V.

    AU - Nave, M.F.F.

    AU - Parail, V.

    AU - Rantamäki, Karin

    AU - Scott, B.D.

    AU - Strand, P.

    AU - Tardini, G.

    AU - Thyagaraja, A.

    AU - Weiland, J.

    AU - Zastrow, K.-D.

    PY - 2007

    Y1 - 2007

    N2 - The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. τE/τphgr ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity χphgreff/χi,eff among different tokamaks can be found. For example, the value of effective Prandtl number is typically around χphgreff/χi,eff ≈ 0.2 on JET while still τE/τphgr ≈ 1 holds. Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number χphgr/χi of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation. The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E × B flow shear and hence modify and can significantly improve the simulation predictions. Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also the Weiland model predict the existence of an anomalous poloidal velocity, peaking in the vicinity of the ITB and driven dominantly by the flow due to the Reynold's stress. It is worth noting that these codes and models treat the equilibrium in a simplified way and this affects the geodesic curvature effects and geodesic acoustic modes. The neo-classical equilibrium is calculated more accurately in the GEM code and the simulations suggest that the spin-up of poloidal velocity is a consequence of the plasma profiles steepening when the ITB grows, following in particular the growth of the toroidal velocity within the ITB.

    AB - The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. τE/τphgr ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity χphgreff/χi,eff among different tokamaks can be found. For example, the value of effective Prandtl number is typically around χphgreff/χi,eff ≈ 0.2 on JET while still τE/τphgr ≈ 1 holds. Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number χphgr/χi of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation. The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E × B flow shear and hence modify and can significantly improve the simulation predictions. Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also the Weiland model predict the existence of an anomalous poloidal velocity, peaking in the vicinity of the ITB and driven dominantly by the flow due to the Reynold's stress. It is worth noting that these codes and models treat the equilibrium in a simplified way and this affects the geodesic curvature effects and geodesic acoustic modes. The neo-classical equilibrium is calculated more accurately in the GEM code and the simulations suggest that the spin-up of poloidal velocity is a consequence of the plasma profiles steepening when the ITB grows, following in particular the growth of the toroidal velocity within the ITB.

    KW - JET

    KW - plasma toroidal confinement

    KW - toroidal momentum transport

    KW - Tokamak

    KW - ITER

    KW - fusion energy

    KW - fusion reactors

    KW - plasma

    U2 - 10.1088/0741-3335/49/12B/S27

    DO - 10.1088/0741-3335/49/12B/S27

    M3 - Article

    VL - 49

    SP - B291-B302

    JO - Plasma Physics and Controlled Fusion

    JF - Plasma Physics and Controlled Fusion

    SN - 0741-3335

    IS - 12B

    ER -