Detection of zonal flow spectra in DIII-D by a dual-channel Doppler backscattering system

L. Schmitz; G. Wang; J. C. Hillesheim; T. L. Rhodes; W. A. Peebles; A. E. White; L. Zeng; T. A. Carter; W. Solomon

doi:10.1063/1.2953675

Detection of zonal flow spectra in DIII-D by a dual-channel Doppler backscattering system

L. Schmitz, G. Wang, J. C. Hillesheim, T. L. Rhodes, W. A. Peebles, A. E. White, L. Zeng, T. A. Carter, W. Solomon

Research output: Contribution to journal › Article › peer-review

38 Scopus citations

Abstract

Doppler backscattering (DBS) has been successfully used to measure the E×B flow velocity and local intermediate wavenumber density fluctuation levels in the DIII-D tokamak. Depending on the launch angle and the frequency of the probing beam, the signal backscattered from the plasma cut-off layer is sensitive to density fluctuations at a specific perpendicular wavenumber (1≤ k⊥ ρ s ≤4). Due to the localization and high time resolution for poloidal flow measurements, DBS is well suited to detect stationary and time-dependent shear flows [zonal flows (ZFs)]. We present a novel scheme to measure ZF spectra using a dual-channel DBS system capable of simultaneously probing two minor radii separated by a distance of 0.2 cm<Δr<3 cm. Frequency spectra of geodesic acoustic modes and low frequency ZFs (f≤10 kHz) have been obtained for 0.6<ra<0.95.

Original language	English
Article number	10F113
Journal	Review of Scientific Instruments
Volume	79
Issue number	10
DOIs	https://doi.org/10.1063/1.2953675
State	Published - 2008
Externally published	Yes

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title = "Detection of zonal flow spectra in DIII-D by a dual-channel Doppler backscattering system",

abstract = "Doppler backscattering (DBS) has been successfully used to measure the E×B flow velocity and local intermediate wavenumber density fluctuation levels in the DIII-D tokamak. Depending on the launch angle and the frequency of the probing beam, the signal backscattered from the plasma cut-off layer is sensitive to density fluctuations at a specific perpendicular wavenumber (1≤ k⊥ ρ s ≤4). Due to the localization and high time resolution for poloidal flow measurements, DBS is well suited to detect stationary and time-dependent shear flows [zonal flows (ZFs)]. We present a novel scheme to measure ZF spectra using a dual-channel DBS system capable of simultaneously probing two minor radii separated by a distance of 0.2 cm<Δr<3 cm. Frequency spectra of geodesic acoustic modes and low frequency ZFs (f≤10 kHz) have been obtained for 0.6",

author = "L. Schmitz and G. Wang and Hillesheim, {J. C.} and Rhodes, {T. L.} and Peebles, {W. A.} and White, {A. E.} and L. Zeng and Carter, {T. A.} and W. Solomon",

year = "2008",

doi = "10.1063/1.2953675",

language = "English",

volume = "79",

journal = "Review of Scientific Instruments",

issn = "0034-6748",

publisher = "American Institute of Physics",

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TY - JOUR

T1 - Detection of zonal flow spectra in DIII-D by a dual-channel Doppler backscattering system

AU - Schmitz, L.

AU - Wang, G.

AU - Hillesheim, J. C.

AU - Rhodes, T. L.

AU - Peebles, W. A.

AU - White, A. E.

AU - Zeng, L.

AU - Carter, T. A.

AU - Solomon, W.

PY - 2008

Y1 - 2008

N2 - Doppler backscattering (DBS) has been successfully used to measure the E×B flow velocity and local intermediate wavenumber density fluctuation levels in the DIII-D tokamak. Depending on the launch angle and the frequency of the probing beam, the signal backscattered from the plasma cut-off layer is sensitive to density fluctuations at a specific perpendicular wavenumber (1≤ k⊥ ρ s ≤4). Due to the localization and high time resolution for poloidal flow measurements, DBS is well suited to detect stationary and time-dependent shear flows [zonal flows (ZFs)]. We present a novel scheme to measure ZF spectra using a dual-channel DBS system capable of simultaneously probing two minor radii separated by a distance of 0.2 cm<Δr<3 cm. Frequency spectra of geodesic acoustic modes and low frequency ZFs (f≤10 kHz) have been obtained for 0.6

AB - Doppler backscattering (DBS) has been successfully used to measure the E×B flow velocity and local intermediate wavenumber density fluctuation levels in the DIII-D tokamak. Depending on the launch angle and the frequency of the probing beam, the signal backscattered from the plasma cut-off layer is sensitive to density fluctuations at a specific perpendicular wavenumber (1≤ k⊥ ρ s ≤4). Due to the localization and high time resolution for poloidal flow measurements, DBS is well suited to detect stationary and time-dependent shear flows [zonal flows (ZFs)]. We present a novel scheme to measure ZF spectra using a dual-channel DBS system capable of simultaneously probing two minor radii separated by a distance of 0.2 cm<Δr<3 cm. Frequency spectra of geodesic acoustic modes and low frequency ZFs (f≤10 kHz) have been obtained for 0.6

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U2 - 10.1063/1.2953675

DO - 10.1063/1.2953675

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JF - Review of Scientific Instruments

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ER -

Detection of zonal flow spectra in DIII-D by a dual-channel Doppler backscattering system

Abstract

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