Transport modelling and gyrokinetic analysis of advanced high performance discharges

J.E. Kinsey, F. Imbeaux, G.M. Staebler, R. Budny, C. Bourdelle, A. Fukuyama, X. Garbet, Tuomas Tala, V. Parail

Research output: Contribution to journalArticleScientificpeer-review

15 Citations (Scopus)

Abstract

Predictive transport modelling and gyrokinetic stability analyses of demonstration hybrid (HYBRID) and advanced tokamak (AT) discharges from the International Tokamak Physics Activity (ITPA) profile database are presented. Both regimes have exhibited enhanced core confinement (above the conventional ITER reference H-mode scenario) but differ in their current density profiles. Recent contributions to the ITPA database have facilitated an effort to study the underlying physics governing confinement in these advanced scenarios. In this paper, we assess the level of commonality of the turbulent transport physics and the relative roles of the transport suppression mechanisms (i.e. E × B shear and Shafranov shift (α) stabilization) using data for select HYBRID and AT discharges from the DIII-D, JET and AUG tokamaks. GLF23 transport modelling and gyrokinetic stability analysis indicate that E × B shear and Shafranov shift stabilization play essential roles in producing the improved core confinement in both HYBRID and AT discharges. Shafranov shift stabilization is found to be more important in AT discharges than in HYBRID discharges. We have also examined the competition between the stabilizing effects of E × B shear and Shafranov shift stabilization and the destabilizing effects of higher safety factors and parallel velocity shear. Linear and nonlinear gyrokinetic simulations of idealized low and high safety factor cases reveal some interesting consequences. A low safety factor (i.e. HYBRID relevant) is directly beneficial in reducing the transport, and E × B shear stabilization can dominate parallel velocity shear destabilization allowing the turbulence to be quenched. However, at low-q/high current, Shafranov shift stabilization plays less of a role. Higher safety factors (as found in AT discharges), on the other hand, have larger amounts of Shafranov shift stabilization, but parallel velocity shear destabilization can prevent E × B shear quenching of the turbulent transport, and only E × B suppression is achieved.
Original languageEnglish
Pages (from-to)450 - 458
Number of pages9
JournalNuclear Fusion
Volume45
Issue number6
DOIs
Publication statusPublished - 2005
MoE publication typeA1 Journal article-refereed

Fingerprint

shear
stabilization
safety factors
shift
physics
destabilization
retarding
commonality
profiles
high current
turbulence
quenching
current density
simulation

Keywords

  • JET
  • plasma
  • fusion energy
  • fusion reactors
  • ITER
  • Tokamak

Cite this

Kinsey, J. E., Imbeaux, F., Staebler, G. M., Budny, R., Bourdelle, C., Fukuyama, A., ... Parail, V. (2005). Transport modelling and gyrokinetic analysis of advanced high performance discharges. Nuclear Fusion, 45(6), 450 - 458. https://doi.org/10.1088/0029-5515/45/6/006
Kinsey, J.E. ; Imbeaux, F. ; Staebler, G.M. ; Budny, R. ; Bourdelle, C. ; Fukuyama, A. ; Garbet, X. ; Tala, Tuomas ; Parail, V. / Transport modelling and gyrokinetic analysis of advanced high performance discharges. In: Nuclear Fusion. 2005 ; Vol. 45, No. 6. pp. 450 - 458.
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Kinsey, JE, Imbeaux, F, Staebler, GM, Budny, R, Bourdelle, C, Fukuyama, A, Garbet, X, Tala, T & Parail, V 2005, 'Transport modelling and gyrokinetic analysis of advanced high performance discharges', Nuclear Fusion, vol. 45, no. 6, pp. 450 - 458. https://doi.org/10.1088/0029-5515/45/6/006

Transport modelling and gyrokinetic analysis of advanced high performance discharges. / Kinsey, J.E.; Imbeaux, F.; Staebler, G.M.; Budny, R.; Bourdelle, C.; Fukuyama, A.; Garbet, X.; Tala, Tuomas; Parail, V.

In: Nuclear Fusion, Vol. 45, No. 6, 2005, p. 450 - 458.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Transport modelling and gyrokinetic analysis of advanced high performance discharges

AU - Kinsey, J.E.

AU - Imbeaux, F.

AU - Staebler, G.M.

AU - Budny, R.

AU - Bourdelle, C.

AU - Fukuyama, A.

AU - Garbet, X.

AU - Tala, Tuomas

AU - Parail, V.

PY - 2005

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N2 - Predictive transport modelling and gyrokinetic stability analyses of demonstration hybrid (HYBRID) and advanced tokamak (AT) discharges from the International Tokamak Physics Activity (ITPA) profile database are presented. Both regimes have exhibited enhanced core confinement (above the conventional ITER reference H-mode scenario) but differ in their current density profiles. Recent contributions to the ITPA database have facilitated an effort to study the underlying physics governing confinement in these advanced scenarios. In this paper, we assess the level of commonality of the turbulent transport physics and the relative roles of the transport suppression mechanisms (i.e. E × B shear and Shafranov shift (α) stabilization) using data for select HYBRID and AT discharges from the DIII-D, JET and AUG tokamaks. GLF23 transport modelling and gyrokinetic stability analysis indicate that E × B shear and Shafranov shift stabilization play essential roles in producing the improved core confinement in both HYBRID and AT discharges. Shafranov shift stabilization is found to be more important in AT discharges than in HYBRID discharges. We have also examined the competition between the stabilizing effects of E × B shear and Shafranov shift stabilization and the destabilizing effects of higher safety factors and parallel velocity shear. Linear and nonlinear gyrokinetic simulations of idealized low and high safety factor cases reveal some interesting consequences. A low safety factor (i.e. HYBRID relevant) is directly beneficial in reducing the transport, and E × B shear stabilization can dominate parallel velocity shear destabilization allowing the turbulence to be quenched. However, at low-q/high current, Shafranov shift stabilization plays less of a role. Higher safety factors (as found in AT discharges), on the other hand, have larger amounts of Shafranov shift stabilization, but parallel velocity shear destabilization can prevent E × B shear quenching of the turbulent transport, and only E × B suppression is achieved.

AB - Predictive transport modelling and gyrokinetic stability analyses of demonstration hybrid (HYBRID) and advanced tokamak (AT) discharges from the International Tokamak Physics Activity (ITPA) profile database are presented. Both regimes have exhibited enhanced core confinement (above the conventional ITER reference H-mode scenario) but differ in their current density profiles. Recent contributions to the ITPA database have facilitated an effort to study the underlying physics governing confinement in these advanced scenarios. In this paper, we assess the level of commonality of the turbulent transport physics and the relative roles of the transport suppression mechanisms (i.e. E × B shear and Shafranov shift (α) stabilization) using data for select HYBRID and AT discharges from the DIII-D, JET and AUG tokamaks. GLF23 transport modelling and gyrokinetic stability analysis indicate that E × B shear and Shafranov shift stabilization play essential roles in producing the improved core confinement in both HYBRID and AT discharges. Shafranov shift stabilization is found to be more important in AT discharges than in HYBRID discharges. We have also examined the competition between the stabilizing effects of E × B shear and Shafranov shift stabilization and the destabilizing effects of higher safety factors and parallel velocity shear. Linear and nonlinear gyrokinetic simulations of idealized low and high safety factor cases reveal some interesting consequences. A low safety factor (i.e. HYBRID relevant) is directly beneficial in reducing the transport, and E × B shear stabilization can dominate parallel velocity shear destabilization allowing the turbulence to be quenched. However, at low-q/high current, Shafranov shift stabilization plays less of a role. Higher safety factors (as found in AT discharges), on the other hand, have larger amounts of Shafranov shift stabilization, but parallel velocity shear destabilization can prevent E × B shear quenching of the turbulent transport, and only E × B suppression is achieved.

KW - JET

KW - plasma

KW - fusion energy

KW - fusion reactors

KW - ITER

KW - Tokamak

U2 - 10.1088/0029-5515/45/6/006

DO - 10.1088/0029-5515/45/6/006

M3 - Article

VL - 45

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JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

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Kinsey JE, Imbeaux F, Staebler GM, Budny R, Bourdelle C, Fukuyama A et al. Transport modelling and gyrokinetic analysis of advanced high performance discharges. Nuclear Fusion. 2005;45(6):450 - 458. https://doi.org/10.1088/0029-5515/45/6/006