Observation of geodesic acoustic mode in EAST using Doppler backscattering system

This paper presents an investigation of the geodesic acoustic mode (GAM) using two poloidally separated Doppler backscattering systems in Experimental Advanced Superconducting Tokamak. Each system allows for the simultaneous measurement of turbulence rotation velocity and density fluctuations with h...

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Bibliographic Details
Published in:Physics of plasmas 2018-09, Vol.25 (9)
Main Authors: Zhang, X. H., Liu, A. D., Zhou, C., Hu, J. Q., Wang, M. Y., Feng, X., Li, C. H., Yang, X. M., Sang, L., Ai, J. Q.
Format: Article
Language:English
Subjects:
Backscattering
Bispectral analysis
Fluid dynamics
Plasma density
Plasma physics
Tokamak devices
Turbulence
Variation
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Summary:This paper presents an investigation of the geodesic acoustic mode (GAM) using two poloidally separated Doppler backscattering systems in Experimental Advanced Superconducting Tokamak. Each system allows for the simultaneous measurement of turbulence rotation velocity and density fluctuations with high precision. With the Doppler backscattering systems, the GAM frequency, the symmetric feature of poloidal flow fluctuations, and the interaction between GAM and turbulence are surveyed. The results of bispectral analysis show a clear interaction of GAM with the ambient turbulence. A clear measurement of GAM in the envelope of plasma density fluctuations using Doppler backscatter system is shown, and the modulations of the turbulence perpendicular velocity on the density turbulence are correlated at two different poloidal position.
ISSN:1070-664X
1089-7674
DOI:10.1063/1.5033432