Blob/hole formation and zonal-flow generation in the edge plasma of the JET tokamak

G.S. Xu; Volker Naulin; W. Fundamenski; C. Hidalgo; J.A. Alonso; C. Silva; B. Goncalves; Anders Henry Nielsen; Jens Juul Rasmussen; S.I. Krasheninnikov; B.N. Wan; M. Stamp

doi:10.1088/0029-5515/49/9/092002

Blob/hole formation and zonal-flow generation in the edge plasma of the JET tokamak

G.S. Xu, Volker Naulin, W. Fundamenski, C. Hidalgo, J.A. Alonso, C. Silva, B. Goncalves, Anders Henry Nielsen, Jens Juul Rasmussen, S.I. Krasheninnikov, B.N. Wan, M. Stamp

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Abstract

The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in the edge plasma of the JET tokamak. Holes as well as blobs are observed to be born in the edge shear layer, where zonal-flows shear off meso-scale coherent structures, leading to disconnection of positive and negative pressure perturbations. The newly formed blobs transport azimuthal momentum up the gradient of the azimuthal flow and drive the zonal-flow shear while moving outwards. During this process energy is transferred from the meso-scale coherent structures to the zonal flows via the turbulent Reynolds stress, resulting in nonlinear saturation of edge turbulence and suppression of meso-scale fluctuations. These findings carry significant implications for the mechanism of structure formation in magnetically confined plasma turbulence.

Original language	English
Journal	Nuclear Fusion
Volume	49
Issue number	9
Pages (from-to)	092002
ISSN	0029-5515
DOIs	https://doi.org/10.1088/0029-5515/49/9/092002
Publication status	Published - 2009

Keywords

Fusion energy

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10.1088/0029-5515/49/9/092002

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title = "Blob/hole formation and zonal-flow generation in the edge plasma of the JET tokamak",

abstract = "The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in the edge plasma of the JET tokamak. Holes as well as blobs are observed to be born in the edge shear layer, where zonal-flows shear off meso-scale coherent structures, leading to disconnection of positive and negative pressure perturbations. The newly formed blobs transport azimuthal momentum up the gradient of the azimuthal flow and drive the zonal-flow shear while moving outwards. During this process energy is transferred from the meso-scale coherent structures to the zonal flows via the turbulent Reynolds stress, resulting in nonlinear saturation of edge turbulence and suppression of meso-scale fluctuations. These findings carry significant implications for the mechanism of structure formation in magnetically confined plasma turbulence.",

keywords = "Fusion energy, Fusionsenergiforskning, Fusionsenergi",

author = "G.S. Xu and Volker Naulin and W. Fundamenski and C. Hidalgo and J.A. Alonso and C. Silva and B. Goncalves and Nielsen, {Anders Henry} and {Juul Rasmussen}, Jens and S.I. Krasheninnikov and B.N. Wan and M. Stamp",

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doi = "10.1088/0029-5515/49/9/092002",

language = "English",

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TY - JOUR

T1 - Blob/hole formation and zonal-flow generation in the edge plasma of the JET tokamak

AU - Xu, G.S.

AU - Naulin, Volker

AU - Fundamenski, W.

AU - Hidalgo, C.

AU - Alonso, J.A.

AU - Silva, C.

AU - Goncalves, B.

AU - Nielsen, Anders Henry

AU - Juul Rasmussen, Jens

AU - Krasheninnikov, S.I.

AU - Wan, B.N.

AU - Stamp, M.

PY - 2009

Y1 - 2009

N2 - The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in the edge plasma of the JET tokamak. Holes as well as blobs are observed to be born in the edge shear layer, where zonal-flows shear off meso-scale coherent structures, leading to disconnection of positive and negative pressure perturbations. The newly formed blobs transport azimuthal momentum up the gradient of the azimuthal flow and drive the zonal-flow shear while moving outwards. During this process energy is transferred from the meso-scale coherent structures to the zonal flows via the turbulent Reynolds stress, resulting in nonlinear saturation of edge turbulence and suppression of meso-scale fluctuations. These findings carry significant implications for the mechanism of structure formation in magnetically confined plasma turbulence.

AB - The first experimental evidence showing the connection between blob/hole formation and zonal-flow generation was obtained in the edge plasma of the JET tokamak. Holes as well as blobs are observed to be born in the edge shear layer, where zonal-flows shear off meso-scale coherent structures, leading to disconnection of positive and negative pressure perturbations. The newly formed blobs transport azimuthal momentum up the gradient of the azimuthal flow and drive the zonal-flow shear while moving outwards. During this process energy is transferred from the meso-scale coherent structures to the zonal flows via the turbulent Reynolds stress, resulting in nonlinear saturation of edge turbulence and suppression of meso-scale fluctuations. These findings carry significant implications for the mechanism of structure formation in magnetically confined plasma turbulence.

KW - Fusion energy

KW - Fusionsenergiforskning

KW - Fusionsenergi

U2 - 10.1088/0029-5515/49/9/092002

DO - 10.1088/0029-5515/49/9/092002

M3 - Journal article

SN - 0029-5515

VL - 49

SP - 092002

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 9

ER -

Blob/hole formation and zonal-flow generation in the edge plasma of the JET tokamak

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