Impact of fast ions on density peaking in JET: Fluid and gyrokinetic modeling

F. Eriksson, M. Oberparleiter, A. Skyman, H. Nordman, P. Strand, A. Salmi, T. Tala, JET Contributors

    Research output: Contribution to journalArticleScientificpeer-review

    2 Citations (Scopus)

    Abstract

    The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position ρ t = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.

    Original languageEnglish
    Article number075008
    Number of pages10
    JournalPlasma Physics and Controlled Fusion
    Volume61
    Issue number7
    DOIs
    Publication statusPublished - 2019
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Fluids
    fluids
    Ions
    ions
    temperature gradients
    beam injection
    neutral beams
    ion temperature
    Thermal gradients
    gradients
    particle flux density
    electron density profiles
    Discharge (fluid mechanics)
    Carrier concentration
    Turbulence
    simulation
    turbulence
    inclusions
    Fluxes
    Electrons

    Keywords

    • Fast ions
    • Fluid
    • Gyrokinetic
    • Particle transport

    Cite this

    Eriksson, F., Oberparleiter, M., Skyman, A., Nordman, H., Strand, P., Salmi, A., ... JET Contributors (2019). Impact of fast ions on density peaking in JET: Fluid and gyrokinetic modeling. Plasma Physics and Controlled Fusion, 61(7), [075008]. https://doi.org/10.1088/1361-6587/ab1e65
    Eriksson, F. ; Oberparleiter, M. ; Skyman, A. ; Nordman, H. ; Strand, P. ; Salmi, A. ; Tala, T. ; JET Contributors. / Impact of fast ions on density peaking in JET : Fluid and gyrokinetic modeling. In: Plasma Physics and Controlled Fusion. 2019 ; Vol. 61, No. 7.
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    abstract = "The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position ρ t = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.",
    keywords = "Fast ions, Fluid, Gyrokinetic, Particle transport",
    author = "F. Eriksson and M. Oberparleiter and A. Skyman and H. Nordman and P. Strand and A. Salmi and T. Tala and {JET Contributors}",
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    Eriksson, F, Oberparleiter, M, Skyman, A, Nordman, H, Strand, P, Salmi, A, Tala, T & JET Contributors 2019, 'Impact of fast ions on density peaking in JET: Fluid and gyrokinetic modeling', Plasma Physics and Controlled Fusion, vol. 61, no. 7, 075008. https://doi.org/10.1088/1361-6587/ab1e65

    Impact of fast ions on density peaking in JET : Fluid and gyrokinetic modeling. / Eriksson, F.; Oberparleiter, M.; Skyman, A.; Nordman, H.; Strand, P.; Salmi, A.; Tala, T.; JET Contributors.

    In: Plasma Physics and Controlled Fusion, Vol. 61, No. 7, 075008, 2019.

    Research output: Contribution to journalArticleScientificpeer-review

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    T1 - Impact of fast ions on density peaking in JET

    T2 - Fluid and gyrokinetic modeling

    AU - Eriksson, F.

    AU - Oberparleiter, M.

    AU - Skyman, A.

    AU - Nordman, H.

    AU - Strand, P.

    AU - Salmi, A.

    AU - Tala, T.

    AU - JET Contributors

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    N2 - The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position ρ t = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.

    AB - The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position ρ t = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.

    KW - Fast ions

    KW - Fluid

    KW - Gyrokinetic

    KW - Particle transport

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