Suppression of electron temperature gradient turbulence via negative magnetic shear in NSTX

H. Y. Yuh; S. M. Kaye; F. M. Levinton; E. Mazzucato; D. R. Mikkelsen; D. R. Smith; R. E. Bell; J. C. Hosea; B. P. Leblanc; J. L. Peterson; H. K. Park; W. Lee

doi:10.1103/PhysRevLett.106.055003

Suppression of electron temperature gradient turbulence via negative magnetic shear in NSTX

H. Y. Yuh, S. M. Kaye, F. M. Levinton, E. Mazzucato, D. R. Mikkelsen, D. R. Smith, R. E. Bell, J. C. Hosea, B. P. Leblanc, J. L. Peterson, H. K. Park, W. Lee

PPPL NSTX

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49 Scopus citations

Abstract

Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regime. Density fluctuation measurements from high-k microwave scattering are verified to be the electron temperature gradient (ETG) mode by matching measured rest frequency and linear growth rate to gyrokinetic calculations. Fluctuation suppression under negligible E×B shear conditions confirm that negative magnetic shear alone is sufficient for ETG suppression. Measured electron temperature gradients can significantly exceed ETG critical gradients with ETG mode activity reduced to intermittent bursts, while electron thermal diffusivity improves to below 0.1 electron gyro-Bohms.

Original language	English (US)
Article number	055003
Journal	Physical review letters
Volume	106
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevLett.106.055003
State	Published - Feb 3 2011

All Science Journal Classification (ASJC) codes

General Physics and Astronomy

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10.1103/PhysRevLett.106.055003

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title = "Suppression of electron temperature gradient turbulence via negative magnetic shear in NSTX",

abstract = "Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regime. Density fluctuation measurements from high-k microwave scattering are verified to be the electron temperature gradient (ETG) mode by matching measured rest frequency and linear growth rate to gyrokinetic calculations. Fluctuation suppression under negligible E×B shear conditions confirm that negative magnetic shear alone is sufficient for ETG suppression. Measured electron temperature gradients can significantly exceed ETG critical gradients with ETG mode activity reduced to intermittent bursts, while electron thermal diffusivity improves to below 0.1 electron gyro-Bohms.",

author = "Yuh, \{H. Y.\} and Kaye, \{S. M.\} and Levinton, \{F. M.\} and E. Mazzucato and Mikkelsen, \{D. R.\} and Smith, \{D. R.\} and Bell, \{R. E.\} and Hosea, \{J. C.\} and Leblanc, \{B. P.\} and Peterson, \{J. L.\} and Park, \{H. K.\} and W. Lee",

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doi = "10.1103/PhysRevLett.106.055003",

language = "English (US)",

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T1 - Suppression of electron temperature gradient turbulence via negative magnetic shear in NSTX

AU - Yuh, H. Y.

AU - Kaye, S. M.

AU - Levinton, F. M.

AU - Mazzucato, E.

AU - Mikkelsen, D. R.

AU - Smith, D. R.

AU - Bell, R. E.

AU - Hosea, J. C.

AU - Leblanc, B. P.

AU - Peterson, J. L.

AU - Park, H. K.

AU - Lee, W.

PY - 2011/2/3

Y1 - 2011/2/3

N2 - Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regime. Density fluctuation measurements from high-k microwave scattering are verified to be the electron temperature gradient (ETG) mode by matching measured rest frequency and linear growth rate to gyrokinetic calculations. Fluctuation suppression under negligible E×B shear conditions confirm that negative magnetic shear alone is sufficient for ETG suppression. Measured electron temperature gradients can significantly exceed ETG critical gradients with ETG mode activity reduced to intermittent bursts, while electron thermal diffusivity improves to below 0.1 electron gyro-Bohms.

AB - Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regime. Density fluctuation measurements from high-k microwave scattering are verified to be the electron temperature gradient (ETG) mode by matching measured rest frequency and linear growth rate to gyrokinetic calculations. Fluctuation suppression under negligible E×B shear conditions confirm that negative magnetic shear alone is sufficient for ETG suppression. Measured electron temperature gradients can significantly exceed ETG critical gradients with ETG mode activity reduced to intermittent bursts, while electron thermal diffusivity improves to below 0.1 electron gyro-Bohms.

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JO - Physical review letters

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ER -

Suppression of electron temperature gradient turbulence via negative magnetic shear in NSTX

Abstract

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