skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment

Abstract

The spherical torus edge region is among the most challenging regimes for plasma turbulence simulations. Here, we measure the spatial and temporal properties of ion-scale turbulence in the steep gradient region of H-mode pedestals during edge localized mode-free, MHD quiescent periods in the National Spherical Torus Experiment. Poloidal correlation lengths are about 10 ρ{sub i}, and decorrelation times are about 5 a/c{sub s}. Next, we introduce a model aggregation technique to identify parametric dependencies among turbulence quantities and transport-relevant plasma parameters. The parametric dependencies show the most agreement with transport driven by trapped-electron mode, kinetic ballooning mode, and microtearing mode turbulence, and the least agreement with ion temperature gradient turbulence. In addition, the parametric dependencies are consistent with turbulence regulation by flow shear and the empirical relationship between wider pedestals and larger turbulent structures.

Authors:
; ; ;  [1]; ; ; ; ; ;  [2]
  1. Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
  2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
Publication Date:
OSTI Identifier:
22228068
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 20; Journal Issue: 5; Other Information: (c) 2013 AIP Publishing LLC; 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; AGGLOMERATION; BALLOONING INSTABILITY; EDGE LOCALIZED MODES; ELECTRON TEMPERATURE; H-MODE PLASMA CONFINEMENT; ION TEMPERATURE; MAGNETOHYDRODYNAMICS; NSTX DEVICE; PLASMA DIAGNOSTICS; PLASMA SIMULATION; SHEAR; TEARING INSTABILITY; TEMPERATURE GRADIENTS; TRAPPED ELECTRONS; TURBULENCE

Citation Formats

Smith, D. R., Fonck, R. J., McKee, G. R., Thompson, D. S., Bell, R. E., Diallo, A., Guttenfelder, W., Kaye, S. M., LeBlanc, B. P., and Podesta, M. Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment. United States: N. p., 2013. Web. doi:10.1063/1.4803913.
Smith, D. R., Fonck, R. J., McKee, G. R., Thompson, D. S., Bell, R. E., Diallo, A., Guttenfelder, W., Kaye, S. M., LeBlanc, B. P., & Podesta, M. Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment. United States. https://doi.org/10.1063/1.4803913
Smith, D. R., Fonck, R. J., McKee, G. R., Thompson, D. S., Bell, R. E., Diallo, A., Guttenfelder, W., Kaye, S. M., LeBlanc, B. P., and Podesta, M. 2013. "Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment". United States. https://doi.org/10.1063/1.4803913.
@article{osti_22228068,
title = {Characterization and parametric dependencies of low wavenumber pedestal turbulence in the National Spherical Torus Experiment},
author = {Smith, D. R. and Fonck, R. J. and McKee, G. R. and Thompson, D. S. and Bell, R. E. and Diallo, A. and Guttenfelder, W. and Kaye, S. M. and LeBlanc, B. P. and Podesta, M.},
abstractNote = {The spherical torus edge region is among the most challenging regimes for plasma turbulence simulations. Here, we measure the spatial and temporal properties of ion-scale turbulence in the steep gradient region of H-mode pedestals during edge localized mode-free, MHD quiescent periods in the National Spherical Torus Experiment. Poloidal correlation lengths are about 10 ρ{sub i}, and decorrelation times are about 5 a/c{sub s}. Next, we introduce a model aggregation technique to identify parametric dependencies among turbulence quantities and transport-relevant plasma parameters. The parametric dependencies show the most agreement with transport driven by trapped-electron mode, kinetic ballooning mode, and microtearing mode turbulence, and the least agreement with ion temperature gradient turbulence. In addition, the parametric dependencies are consistent with turbulence regulation by flow shear and the empirical relationship between wider pedestals and larger turbulent structures.},
doi = {10.1063/1.4803913},
url = {https://www.osti.gov/biblio/22228068}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 20,
place = {United States},
year = {Wed May 15 00:00:00 EDT 2013},
month = {Wed May 15 00:00:00 EDT 2013}
}