Resolving the mystery of transport within internal transport barriers

G. M. Staebler; J. E. Kinsey; E. A. Belli; J. Candy; R. E. Waltz; C. M. Greenfield; L. L. Lao; S. P. Smith; B. A. Grierson; C. Chrystal

doi:10.1063/1.4875334

Resolving the mystery of transport within internal transport barriers

G. M. Staebler, J. E. Kinsey, E. A. Belli, J. Candy, R. E. Waltz, C. M. Greenfield, L. L. Lao, S. P. Smith, B. A. Grierson, C. Chrystal

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12 Scopus citations

Abstract

The Trapped Gyro-Landau Fluid (TGLF) quasi-linear model [G. M. Staebler, et al., Phys. Plasmas 12, 102508 (2005)], which is calibrated to nonlinear gyrokinetic turbulence simulations, is now able to predict the electron density, electron and ion temperatures, and ion toroidal rotation simultaneously for internal transport barrier (ITB) discharges. This is a strong validation of gyrokinetic theory of ITBs, requiring multiple instabilities responsible for transport in different channels at different scales. The mystery of transport inside the ITB is that momentum and particle transport is far above the predicted neoclassical levels in apparent contradiction with the expectation from the theory of suppression of turbulence by E×B velocity shear. The success of TGLF in predicting ITB transport is due to the inclusion of ion gyro-radius scale modes that become dominant at high E×B velocity shear and to improvements to TGLF that allow momentum transport from gyrokinetic turbulence to be faithfully modeled.

Original language	English
Article number	055902
Journal	Physics of Plasmas
Volume	21
Issue number	5
DOIs	https://doi.org/10.1063/1.4875334
State	Published - May 2014
Externally published	Yes

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title = "Resolving the mystery of transport within internal transport barriers",

abstract = "The Trapped Gyro-Landau Fluid (TGLF) quasi-linear model [G. M. Staebler, et al., Phys. Plasmas 12, 102508 (2005)], which is calibrated to nonlinear gyrokinetic turbulence simulations, is now able to predict the electron density, electron and ion temperatures, and ion toroidal rotation simultaneously for internal transport barrier (ITB) discharges. This is a strong validation of gyrokinetic theory of ITBs, requiring multiple instabilities responsible for transport in different channels at different scales. The mystery of transport inside the ITB is that momentum and particle transport is far above the predicted neoclassical levels in apparent contradiction with the expectation from the theory of suppression of turbulence by E×B velocity shear. The success of TGLF in predicting ITB transport is due to the inclusion of ion gyro-radius scale modes that become dominant at high E×B velocity shear and to improvements to TGLF that allow momentum transport from gyrokinetic turbulence to be faithfully modeled.",

author = "Staebler, {G. M.} and Kinsey, {J. E.} and Belli, {E. A.} and J. Candy and Waltz, {R. E.} and Greenfield, {C. M.} and Lao, {L. L.} and Smith, {S. P.} and Grierson, {B. A.} and C. Chrystal",

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AU - Kinsey, J. E.

AU - Belli, E. A.

AU - Candy, J.

AU - Waltz, R. E.

AU - Greenfield, C. M.

AU - Lao, L. L.

AU - Smith, S. P.

AU - Grierson, B. A.

AU - Chrystal, C.

PY - 2014/5

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Resolving the mystery of transport within internal transport barriers

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