Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection

M. Valisa, L. Carraro, I. Predebon, M.E. Puiatti, C. Angioni, I. Coffey, Carine Giroud, L. Lauro-Taroni, B. Alper, M. Baruzzo, P. Belo Dasilva, P. Buratti, L. Garzotti, D. Van Eester, E. Lerche, P. Mantica, V. Naulin, Tuomas Tala, M. Tsalas

    Research output: Contribution to journalArticleScientificpeer-review

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    Abstract

    The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.

    Original languageEnglish
    Article number033002
    Number of pages11
    JournalNuclear Fusion
    Volume51
    Issue number3
    DOIs
    Publication statusPublished - 1 Mar 2011
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    cyclotrons
    injection
    impurities
    heating
    metals
    ions
    hollow
    profiles
    poloidal flux
    radial flow
    ion temperature
    radial velocity
    diffusivity
    temperature gradients
    convection
    turbulence
    electrostatics
    pumps
    perturbation
    radii

    Cite this

    Valisa, M., Carraro, L., Predebon, I., Puiatti, M. E., Angioni, C., Coffey, I., ... Tsalas, M. (2011). Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection. Nuclear Fusion, 51(3), [033002]. https://doi.org/10.1088/0029-5515/51/3/033002
    Valisa, M. ; Carraro, L. ; Predebon, I. ; Puiatti, M.E. ; Angioni, C. ; Coffey, I. ; Giroud, Carine ; Lauro-Taroni, L. ; Alper, B. ; Baruzzo, M. ; Belo Dasilva, P. ; Buratti, P. ; Garzotti, L. ; Van Eester, D. ; Lerche, E. ; Mantica, P. ; Naulin, V. ; Tala, Tuomas ; Tsalas, M. / Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection. In: Nuclear Fusion. 2011 ; Vol. 51, No. 3.
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    title = "Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection",
    abstract = "The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.",
    author = "M. Valisa and L. Carraro and I. Predebon and M.E. Puiatti and C. Angioni and I. Coffey and Carine Giroud and L. Lauro-Taroni and B. Alper and M. Baruzzo and {Belo Dasilva}, P. and P. Buratti and L. Garzotti and {Van Eester}, D. and E. Lerche and P. Mantica and V. Naulin and Tuomas Tala and M. Tsalas",
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    Valisa, M, Carraro, L, Predebon, I, Puiatti, ME, Angioni, C, Coffey, I, Giroud, C, Lauro-Taroni, L, Alper, B, Baruzzo, M, Belo Dasilva, P, Buratti, P, Garzotti, L, Van Eester, D, Lerche, E, Mantica, P, Naulin, V, Tala, T & Tsalas, M 2011, 'Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection', Nuclear Fusion, vol. 51, no. 3, 033002. https://doi.org/10.1088/0029-5515/51/3/033002

    Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection. / Valisa, M.; Carraro, L.; Predebon, I.; Puiatti, M.E.; Angioni, C.; Coffey, I.; Giroud, Carine; Lauro-Taroni, L.; Alper, B.; Baruzzo, M.; Belo Dasilva, P.; Buratti, P.; Garzotti, L.; Van Eester, D.; Lerche, E.; Mantica, P.; Naulin, V.; Tala, Tuomas; Tsalas, M.

    In: Nuclear Fusion, Vol. 51, No. 3, 033002, 01.03.2011.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection

    AU - Valisa, M.

    AU - Carraro, L.

    AU - Predebon, I.

    AU - Puiatti, M.E.

    AU - Angioni, C.

    AU - Coffey, I.

    AU - Giroud, Carine

    AU - Lauro-Taroni, L.

    AU - Alper, B.

    AU - Baruzzo, M.

    AU - Belo Dasilva, P.

    AU - Buratti, P.

    AU - Garzotti, L.

    AU - Van Eester, D.

    AU - Lerche, E.

    AU - Mantica, P.

    AU - Naulin, V.

    AU - Tala, Tuomas

    AU - Tsalas, M.

    PY - 2011/3/1

    Y1 - 2011/3/1

    N2 - The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.

    AB - The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.

    U2 - 10.1088/0029-5515/51/3/033002

    DO - 10.1088/0029-5515/51/3/033002

    M3 - Article

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    VL - 51

    JO - Nuclear Fusion

    JF - Nuclear Fusion

    SN - 0029-5515

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    M1 - 033002

    ER -