Density Peaking in JET - Driven by Fuelling or Transport?

T. Tala (Corresponding Author), H. Nordman, A. Salmi, C. Bourdelle, J. Citrin, A. Czarnecka, F. Eriksson, E. Fransson, C. Giroud, J. Hillesheim, C. Maggi, P. Mantica, A. Mariani, M. Maslov, L. Meneses, S. Menmuir, S. Mordijck, V. Naulin, M. Oberparleiter, G. SipsD. Tegnered, M. Tsalas, H. Weisen, JET Contributors

    Research output: Contribution to journalArticleScientificpeer-review

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    Abstract

    Core density profile peaking and electron particle transport have been extensively studied by performing several dimensionless collisionality (υ *) scans with other matched dimensionless profiles in various plasma operation scenarios on the Joint European Torus (JET). This is the first time when electron particle transport coefficients in the H-mode have been measured on JET with high resolution diagnostics, and therefore we are in a position to distinguish between the neutral beam injection (NBI) source and inward electron particle pinch in contributing to core density peaking. The NBI particle source is found to contribute typically 50%–60% to the electron density peaking in JET H-mode plasmas where T e/T i ~ 1 or smaller and at υ *  =  0.1–0.5 (averaged between r/a  =  0.3–0.8), and being independent of υ * within that range. In these H-mode plasmas, the electron particle transport coefficients, D e and v e, are small, thus giving rise to the large influence of NBI fueling with respect to transport effect on peaking. In L-mode plasma conditions, the role of the NBI source is small, typically 10%–20%, and the electron particle transport coefficients are large. These dimensionless υ * scans give the best possible data for model validation. TGLF simulations are in good agreement with the experimental results with respect to the role of NBI particle source versus inward pinch in affecting density peaking, both for the H-mode and L-mode υ * scans. It predicts, similarly to experimental results, that typically about half of the peaking originates from the NBI fuelling in the H-mode and 10%–20% in the L-mode. GENE simulation results also support the key role of NBI fuelling in causing a peaked density profile in JET H-mode plasma (T e/T i ~ 1 and υ *  =  0.1–0.5) and, in fact, give an even higher weight on NBI fuelling than that experimentally observed or predicted by TGLF. For the non-fuelled H-mode plasma at higher T e/T i  =  1.5 and lower β N and υ *, both TGLF and GENE predict peaked density profiles, therefore agreeing well with experimental steady-state density peaking. Overall, the various modelling results give a fairly good confidence in using TGLF and GENE in predicting density peaking in quite a wide range of plasma conditions in JET.
    Original languageEnglish
    Article number126030
    JournalNuclear Fusion
    Volume59
    Issue number12
    DOIs
    Publication statusPublished - 11 Oct 2019
    MoE publication typeA1 Journal article-refereed

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    Joint European Torus
    refueling
    beam injection
    neutral beams
    transport properties
    profiles
    electrons
    confidence
    simulation

    Cite this

    Tala, T., Nordman, H., Salmi, A., Bourdelle, C., Citrin, J., Czarnecka, A., ... JET Contributors (2019). Density Peaking in JET - Driven by Fuelling or Transport? Nuclear Fusion, 59(12), [126030]. https://doi.org/10.1088/1741-4326/ab4248
    Tala, T. ; Nordman, H. ; Salmi, A. ; Bourdelle, C. ; Citrin, J. ; Czarnecka, A. ; Eriksson, F. ; Fransson, E. ; Giroud, C. ; Hillesheim, J. ; Maggi, C. ; Mantica, P. ; Mariani, A. ; Maslov, M. ; Meneses, L. ; Menmuir, S. ; Mordijck, S. ; Naulin, V. ; Oberparleiter, M. ; Sips, G. ; Tegnered, D. ; Tsalas, M. ; Weisen, H. ; JET Contributors. / Density Peaking in JET - Driven by Fuelling or Transport?. In: Nuclear Fusion. 2019 ; Vol. 59, No. 12.
    @article{6bd78d7b5e4247a491f8b89e911f7170,
    title = "Density Peaking in JET - Driven by Fuelling or Transport?",
    abstract = "Core density profile peaking and electron particle transport have been extensively studied by performing several dimensionless collisionality (υ *) scans with other matched dimensionless profiles in various plasma operation scenarios on the Joint European Torus (JET). This is the first time when electron particle transport coefficients in the H-mode have been measured on JET with high resolution diagnostics, and therefore we are in a position to distinguish between the neutral beam injection (NBI) source and inward electron particle pinch in contributing to core density peaking. The NBI particle source is found to contribute typically 50{\%}–60{\%} to the electron density peaking in JET H-mode plasmas where T e/T i ~ 1 or smaller and at υ *  =  0.1–0.5 (averaged between r/a  =  0.3–0.8), and being independent of υ * within that range. In these H-mode plasmas, the electron particle transport coefficients, D e and v e, are small, thus giving rise to the large influence of NBI fueling with respect to transport effect on peaking. In L-mode plasma conditions, the role of the NBI source is small, typically 10{\%}–20{\%}, and the electron particle transport coefficients are large. These dimensionless υ * scans give the best possible data for model validation. TGLF simulations are in good agreement with the experimental results with respect to the role of NBI particle source versus inward pinch in affecting density peaking, both for the H-mode and L-mode υ * scans. It predicts, similarly to experimental results, that typically about half of the peaking originates from the NBI fuelling in the H-mode and 10{\%}–20{\%} in the L-mode. GENE simulation results also support the key role of NBI fuelling in causing a peaked density profile in JET H-mode plasma (T e/T i ~ 1 and υ *  =  0.1–0.5) and, in fact, give an even higher weight on NBI fuelling than that experimentally observed or predicted by TGLF. For the non-fuelled H-mode plasma at higher T e/T i  =  1.5 and lower β N and υ *, both TGLF and GENE predict peaked density profiles, therefore agreeing well with experimental steady-state density peaking. Overall, the various modelling results give a fairly good confidence in using TGLF and GENE in predicting density peaking in quite a wide range of plasma conditions in JET.",
    author = "T. Tala and H. Nordman and A. Salmi and C. Bourdelle and J. Citrin and A. Czarnecka and F. Eriksson and E. Fransson and C. Giroud and J. Hillesheim and C. Maggi and P. Mantica and A. Mariani and M. Maslov and L. Meneses and S. Menmuir and S. Mordijck and V. Naulin and M. Oberparleiter and G. Sips and D. Tegnered and M. Tsalas and H. Weisen and {JET Contributors}",
    year = "2019",
    month = "10",
    day = "11",
    doi = "10.1088/1741-4326/ab4248",
    language = "English",
    volume = "59",
    journal = "Nuclear Fusion",
    issn = "0029-5515",
    publisher = "Institute of Physics IOP",
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    Tala, T, Nordman, H, Salmi, A, Bourdelle, C, Citrin, J, Czarnecka, A, Eriksson, F, Fransson, E, Giroud, C, Hillesheim, J, Maggi, C, Mantica, P, Mariani, A, Maslov, M, Meneses, L, Menmuir, S, Mordijck, S, Naulin, V, Oberparleiter, M, Sips, G, Tegnered, D, Tsalas, M, Weisen, H & JET Contributors 2019, 'Density Peaking in JET - Driven by Fuelling or Transport?', Nuclear Fusion, vol. 59, no. 12, 126030. https://doi.org/10.1088/1741-4326/ab4248

    Density Peaking in JET - Driven by Fuelling or Transport? / Tala, T. (Corresponding Author); Nordman, H.; Salmi, A.; Bourdelle, C.; Citrin, J.; Czarnecka, A.; Eriksson, F.; Fransson, E.; Giroud, C.; Hillesheim, J.; Maggi, C.; Mantica, P.; Mariani, A.; Maslov, M.; Meneses, L.; Menmuir, S.; Mordijck, S.; Naulin, V.; Oberparleiter, M.; Sips, G.; Tegnered, D.; Tsalas, M.; Weisen, H.; JET Contributors.

    In: Nuclear Fusion, Vol. 59, No. 12, 126030, 11.10.2019.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Density Peaking in JET - Driven by Fuelling or Transport?

    AU - Tala, T.

    AU - Nordman, H.

    AU - Salmi, A.

    AU - Bourdelle, C.

    AU - Citrin, J.

    AU - Czarnecka, A.

    AU - Eriksson, F.

    AU - Fransson, E.

    AU - Giroud, C.

    AU - Hillesheim, J.

    AU - Maggi, C.

    AU - Mantica, P.

    AU - Mariani, A.

    AU - Maslov, M.

    AU - Meneses, L.

    AU - Menmuir, S.

    AU - Mordijck, S.

    AU - Naulin, V.

    AU - Oberparleiter, M.

    AU - Sips, G.

    AU - Tegnered, D.

    AU - Tsalas, M.

    AU - Weisen, H.

    AU - JET Contributors

    PY - 2019/10/11

    Y1 - 2019/10/11

    N2 - Core density profile peaking and electron particle transport have been extensively studied by performing several dimensionless collisionality (υ *) scans with other matched dimensionless profiles in various plasma operation scenarios on the Joint European Torus (JET). This is the first time when electron particle transport coefficients in the H-mode have been measured on JET with high resolution diagnostics, and therefore we are in a position to distinguish between the neutral beam injection (NBI) source and inward electron particle pinch in contributing to core density peaking. The NBI particle source is found to contribute typically 50%–60% to the electron density peaking in JET H-mode plasmas where T e/T i ~ 1 or smaller and at υ *  =  0.1–0.5 (averaged between r/a  =  0.3–0.8), and being independent of υ * within that range. In these H-mode plasmas, the electron particle transport coefficients, D e and v e, are small, thus giving rise to the large influence of NBI fueling with respect to transport effect on peaking. In L-mode plasma conditions, the role of the NBI source is small, typically 10%–20%, and the electron particle transport coefficients are large. These dimensionless υ * scans give the best possible data for model validation. TGLF simulations are in good agreement with the experimental results with respect to the role of NBI particle source versus inward pinch in affecting density peaking, both for the H-mode and L-mode υ * scans. It predicts, similarly to experimental results, that typically about half of the peaking originates from the NBI fuelling in the H-mode and 10%–20% in the L-mode. GENE simulation results also support the key role of NBI fuelling in causing a peaked density profile in JET H-mode plasma (T e/T i ~ 1 and υ *  =  0.1–0.5) and, in fact, give an even higher weight on NBI fuelling than that experimentally observed or predicted by TGLF. For the non-fuelled H-mode plasma at higher T e/T i  =  1.5 and lower β N and υ *, both TGLF and GENE predict peaked density profiles, therefore agreeing well with experimental steady-state density peaking. Overall, the various modelling results give a fairly good confidence in using TGLF and GENE in predicting density peaking in quite a wide range of plasma conditions in JET.

    AB - Core density profile peaking and electron particle transport have been extensively studied by performing several dimensionless collisionality (υ *) scans with other matched dimensionless profiles in various plasma operation scenarios on the Joint European Torus (JET). This is the first time when electron particle transport coefficients in the H-mode have been measured on JET with high resolution diagnostics, and therefore we are in a position to distinguish between the neutral beam injection (NBI) source and inward electron particle pinch in contributing to core density peaking. The NBI particle source is found to contribute typically 50%–60% to the electron density peaking in JET H-mode plasmas where T e/T i ~ 1 or smaller and at υ *  =  0.1–0.5 (averaged between r/a  =  0.3–0.8), and being independent of υ * within that range. In these H-mode plasmas, the electron particle transport coefficients, D e and v e, are small, thus giving rise to the large influence of NBI fueling with respect to transport effect on peaking. In L-mode plasma conditions, the role of the NBI source is small, typically 10%–20%, and the electron particle transport coefficients are large. These dimensionless υ * scans give the best possible data for model validation. TGLF simulations are in good agreement with the experimental results with respect to the role of NBI particle source versus inward pinch in affecting density peaking, both for the H-mode and L-mode υ * scans. It predicts, similarly to experimental results, that typically about half of the peaking originates from the NBI fuelling in the H-mode and 10%–20% in the L-mode. GENE simulation results also support the key role of NBI fuelling in causing a peaked density profile in JET H-mode plasma (T e/T i ~ 1 and υ *  =  0.1–0.5) and, in fact, give an even higher weight on NBI fuelling than that experimentally observed or predicted by TGLF. For the non-fuelled H-mode plasma at higher T e/T i  =  1.5 and lower β N and υ *, both TGLF and GENE predict peaked density profiles, therefore agreeing well with experimental steady-state density peaking. Overall, the various modelling results give a fairly good confidence in using TGLF and GENE in predicting density peaking in quite a wide range of plasma conditions in JET.

    UR - http://www.scopus.com/inward/record.url?scp=85074901674&partnerID=8YFLogxK

    U2 - 10.1088/1741-4326/ab4248

    DO - 10.1088/1741-4326/ab4248

    M3 - Article

    VL - 59

    JO - Nuclear Fusion

    JF - Nuclear Fusion

    SN - 0029-5515

    IS - 12

    M1 - 126030

    ER -

    Tala T, Nordman H, Salmi A, Bourdelle C, Citrin J, Czarnecka A et al. Density Peaking in JET - Driven by Fuelling or Transport? Nuclear Fusion. 2019 Oct 11;59(12). 126030. https://doi.org/10.1088/1741-4326/ab4248