Scale-selective turbulence reduction in H-mode plasmas in the TJ-II stellarator

T. Happel; T. Estrada; E. Blanco; C. Hidalgo; G. D. Conway; U. Stroth

doi:10.1063/1.3646315

Scale-selective turbulence reduction in H-mode plasmas in the TJ-II stellarator

T. Happel, T. Estrada, E. Blanco, C. Hidalgo, G. D. Conway, U. Stroth

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Abstract

Wavenumber spectra of density turbulence in L- and H-mode plasmas have been measured in the TJ-II stellarator by means of Doppler reflectometry. A pronounced suppression of the density fluctuation level is observed in H-mode close to the radial position of maximum radial electric field (E_r) shear. Furthermore, intermediate scale density turbulence is reduced preferentially. This effect can be interpreted within the framework of vortex stretching feeding energy through Reynolds stress into zonal flows, while shear decorrelation of turbulent structures might not play a central role in TJ-II. Moreover, it is shown that in both L- and H-mode, the phase velocity of density fluctuations does not depend on the structure scale.

Original language	English
Article number	102302
Journal	Physics of Plasmas
Volume	18
Issue number	10
DOIs	https://doi.org/10.1063/1.3646315
State	Published - Oct 2011
Externally published	Yes

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title = "Scale-selective turbulence reduction in H-mode plasmas in the TJ-II stellarator",

abstract = "Wavenumber spectra of density turbulence in L- and H-mode plasmas have been measured in the TJ-II stellarator by means of Doppler reflectometry. A pronounced suppression of the density fluctuation level is observed in H-mode close to the radial position of maximum radial electric field (Er) shear. Furthermore, intermediate scale density turbulence is reduced preferentially. This effect can be interpreted within the framework of vortex stretching feeding energy through Reynolds stress into zonal flows, while shear decorrelation of turbulent structures might not play a central role in TJ-II. Moreover, it is shown that in both L- and H-mode, the phase velocity of density fluctuations does not depend on the structure scale.",

author = "T. Happel and T. Estrada and E. Blanco and C. Hidalgo and Conway, {G. D.} and U. Stroth",

note = "Funding Information: The authors gratefully acknowledge the TJ-II team for conducting the experiments. This work was partially funded by the Spanish Ministry of Science and Innovation under Contract No. ENE2010-18409, which is gratefully acknowledged.",

year = "2011",

month = oct,

doi = "10.1063/1.3646315",

language = "English",

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TY - JOUR

T1 - Scale-selective turbulence reduction in H-mode plasmas in the TJ-II stellarator

AU - Happel, T.

AU - Estrada, T.

AU - Blanco, E.

AU - Hidalgo, C.

AU - Conway, G. D.

AU - Stroth, U.

N1 - Funding Information: The authors gratefully acknowledge the TJ-II team for conducting the experiments. This work was partially funded by the Spanish Ministry of Science and Innovation under Contract No. ENE2010-18409, which is gratefully acknowledged.

PY - 2011/10

Y1 - 2011/10

N2 - Wavenumber spectra of density turbulence in L- and H-mode plasmas have been measured in the TJ-II stellarator by means of Doppler reflectometry. A pronounced suppression of the density fluctuation level is observed in H-mode close to the radial position of maximum radial electric field (Er) shear. Furthermore, intermediate scale density turbulence is reduced preferentially. This effect can be interpreted within the framework of vortex stretching feeding energy through Reynolds stress into zonal flows, while shear decorrelation of turbulent structures might not play a central role in TJ-II. Moreover, it is shown that in both L- and H-mode, the phase velocity of density fluctuations does not depend on the structure scale.

AB - Wavenumber spectra of density turbulence in L- and H-mode plasmas have been measured in the TJ-II stellarator by means of Doppler reflectometry. A pronounced suppression of the density fluctuation level is observed in H-mode close to the radial position of maximum radial electric field (Er) shear. Furthermore, intermediate scale density turbulence is reduced preferentially. This effect can be interpreted within the framework of vortex stretching feeding energy through Reynolds stress into zonal flows, while shear decorrelation of turbulent structures might not play a central role in TJ-II. Moreover, it is shown that in both L- and H-mode, the phase velocity of density fluctuations does not depend on the structure scale.

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DO - 10.1063/1.3646315

M3 - Article

AN - SCOPUS:80655142595

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VL - 18

JO - Physics of Plasmas

JF - Physics of Plasmas

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M1 - 102302

ER -

Scale-selective turbulence reduction in H-mode plasmas in the TJ-II stellarator

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