Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus

A. Casati (Corresponding Author), P. Mantica, D. Van Eester, N. Hawkes, F. Imbeaux, E. Joffrin, A. Marinoni, F. Ryter, A. Salmi, Tuomas Tala, P. De Vries

    Research output: Contribution to journalArticleScientificpeer-review

    8 Citations (Scopus)

    Abstract

    New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented.
    The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot.
    Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold.
    The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented.
    The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed.
    Original languageEnglish
    Article number092303
    JournalPhysics of Plasmas
    Volume14
    Issue number9
    DOIs
    Publication statusPublished - 2007
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Joint European Torus
    wave propagation
    temperature gradients
    critical temperature
    signatures
    heat
    thresholds
    barrier layers
    cyclotron resonance
    temperature profiles
    stiffness
    electrons
    fusion
    damping
    modulation
    perturbation
    gradients
    oscillations
    heating
    propagation

    Keywords

    • plasma
    • plasma radiofrequency heating
    • plasma temperature
    • plasma toroidal confinement
    • plasma transport processes
    • plasma turbulence
    • JET
    • internal transport barriers
    • fusion energy
    • fusion reactors

    Cite this

    Casati, A., Mantica, P., Van Eester, D., Hawkes, N., Imbeaux, F., Joffrin, E., ... De Vries, P. (2007). Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus. Physics of Plasmas, 14(9), [092303]. https://doi.org/10.1063/1.2772618
    Casati, A. ; Mantica, P. ; Van Eester, D. ; Hawkes, N. ; Imbeaux, F. ; Joffrin, E. ; Marinoni, A. ; Ryter, F. ; Salmi, A. ; Tala, Tuomas ; De Vries, P. / Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus. In: Physics of Plasmas. 2007 ; Vol. 14, No. 9.
    @article{3d682984bcad45f3b740702502a1f749,
    title = "Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus",
    abstract = "New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented. The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot. Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold. The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented. The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed.",
    keywords = "plasma, plasma radiofrequency heating, plasma temperature, plasma toroidal confinement, plasma transport processes, plasma turbulence, JET, internal transport barriers, fusion energy, fusion reactors",
    author = "A. Casati and P. Mantica and {Van Eester}, D. and N. Hawkes and F. Imbeaux and E. Joffrin and A. Marinoni and F. Ryter and A. Salmi and Tuomas Tala and {De Vries}, P.",
    year = "2007",
    doi = "10.1063/1.2772618",
    language = "English",
    volume = "14",
    journal = "Physics of Plasmas",
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    Casati, A, Mantica, P, Van Eester, D, Hawkes, N, Imbeaux, F, Joffrin, E, Marinoni, A, Ryter, F, Salmi, A, Tala, T & De Vries, P 2007, 'Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus', Physics of Plasmas, vol. 14, no. 9, 092303. https://doi.org/10.1063/1.2772618

    Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus. / Casati, A. (Corresponding Author); Mantica, P.; Van Eester, D.; Hawkes, N.; Imbeaux, F.; Joffrin, E.; Marinoni, A.; Ryter, F.; Salmi, A.; Tala, Tuomas; De Vries, P.

    In: Physics of Plasmas, Vol. 14, No. 9, 092303, 2007.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus

    AU - Casati, A.

    AU - Mantica, P.

    AU - Van Eester, D.

    AU - Hawkes, N.

    AU - Imbeaux, F.

    AU - Joffrin, E.

    AU - Marinoni, A.

    AU - Ryter, F.

    AU - Salmi, A.

    AU - Tala, Tuomas

    AU - De Vries, P.

    PY - 2007

    Y1 - 2007

    N2 - New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented. The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot. Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold. The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented. The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed.

    AB - New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented. The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot. Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold. The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented. The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed.

    KW - plasma

    KW - plasma radiofrequency heating

    KW - plasma temperature

    KW - plasma toroidal confinement

    KW - plasma transport processes

    KW - plasma turbulence

    KW - JET

    KW - internal transport barriers

    KW - fusion energy

    KW - fusion reactors

    U2 - 10.1063/1.2772618

    DO - 10.1063/1.2772618

    M3 - Article

    VL - 14

    JO - Physics of Plasmas

    JF - Physics of Plasmas

    SN - 1527-2419

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