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Title: Multiscale coherent structures in tokamak plasma turbulence

Abstract

A 12-tip poloidal probe array is used on the HT-7 superconducting tokamak [Li, Wan, and Mao, Plasma Phys. Controlled Fusion 42, 135 (2000)] to measure plasma turbulence in the edge region. Some statistical analysis techniques are used to characterize the turbulence structures. It is found that the plasma turbulence is composed of multiscale coherent structures, i.e., turbulent eddies and there is self-similarity in a relative short scale range. The presence of the self-similarity is found due to the structural similarity of these eddies between different scales. These turbulent eddies constitute the basic convection cells, so the self-similar range is just the dominant scale range relevant to transport. The experimental results also indicate that the plasma turbulence is dominated by low-frequency and long-wavelength fluctuation components and its dispersion relation shows typical electron-drift-wave characteristics. Some large-scale coherent structures intermittently burst out and exhibit a very long poloidal extent, even longer than 6 cm. It is found that these large-scale coherent structures are mainly contributed by the low-frequency and long-wavelength fluctuating components and their presence is responsible for the observations of long-range correlations, i.e., the correlation in the scale range much longer than the turbulence decorrelation scale. These experimental observations suggest that themore » coexistence of multiscale coherent structures results in the self-similar turbulent state.« less

Authors:
; ; ; ; ;  [1]
  1. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)
Publication Date:
OSTI Identifier:
20860312
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 13; Journal Issue: 10; Other Information: DOI: 10.1063/1.2357045; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOUNDARY LAYERS; CONVECTION; CORRELATIONS; DISPERSION RELATIONS; ELECTRON DRIFT; FLUCTUATIONS; FRACTALS; PLASMA; PLASMA CONFINEMENT; PLASMA DRIFT; PROBES; RADIATION TRANSPORT; TOKAMAK DEVICES; TURBULENCE; WAVELENGTHS

Citation Formats

Xu, G S, Wan, B N, Zhang, W, Yang, Q W, Wang, L, Wen, Y Z, Southwestern Institute of Physics, Chengdu 610041, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, and University of Science and Technology of China, Hefei 230026. Multiscale coherent structures in tokamak plasma turbulence. United States: N. p., 2006. Web. doi:10.1063/1.2357045.
Xu, G S, Wan, B N, Zhang, W, Yang, Q W, Wang, L, Wen, Y Z, Southwestern Institute of Physics, Chengdu 610041, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, & University of Science and Technology of China, Hefei 230026. Multiscale coherent structures in tokamak plasma turbulence. United States. https://doi.org/10.1063/1.2357045
Xu, G S, Wan, B N, Zhang, W, Yang, Q W, Wang, L, Wen, Y Z, Southwestern Institute of Physics, Chengdu 610041, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, and University of Science and Technology of China, Hefei 230026. 2006. "Multiscale coherent structures in tokamak plasma turbulence". United States. https://doi.org/10.1063/1.2357045.
@article{osti_20860312,
title = {Multiscale coherent structures in tokamak plasma turbulence},
author = {Xu, G S and Wan, B N and Zhang, W and Yang, Q W and Wang, L and Wen, Y Z and Southwestern Institute of Physics, Chengdu 610041 and Institute of Physics, Chinese Academy of Sciences, Beijing 100080 and University of Science and Technology of China, Hefei 230026},
abstractNote = {A 12-tip poloidal probe array is used on the HT-7 superconducting tokamak [Li, Wan, and Mao, Plasma Phys. Controlled Fusion 42, 135 (2000)] to measure plasma turbulence in the edge region. Some statistical analysis techniques are used to characterize the turbulence structures. It is found that the plasma turbulence is composed of multiscale coherent structures, i.e., turbulent eddies and there is self-similarity in a relative short scale range. The presence of the self-similarity is found due to the structural similarity of these eddies between different scales. These turbulent eddies constitute the basic convection cells, so the self-similar range is just the dominant scale range relevant to transport. The experimental results also indicate that the plasma turbulence is dominated by low-frequency and long-wavelength fluctuation components and its dispersion relation shows typical electron-drift-wave characteristics. Some large-scale coherent structures intermittently burst out and exhibit a very long poloidal extent, even longer than 6 cm. It is found that these large-scale coherent structures are mainly contributed by the low-frequency and long-wavelength fluctuating components and their presence is responsible for the observations of long-range correlations, i.e., the correlation in the scale range much longer than the turbulence decorrelation scale. These experimental observations suggest that the coexistence of multiscale coherent structures results in the self-similar turbulent state.},
doi = {10.1063/1.2357045},
url = {https://www.osti.gov/biblio/20860312}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 10,
volume = 13,
place = {United States},
year = {Sun Oct 15 00:00:00 EDT 2006},
month = {Sun Oct 15 00:00:00 EDT 2006}
}