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Title: Effect of secondary convective cells on turbulence intensity profiles, flow generation, and transport

Abstract

This paper reports the results of gyrokinetic simulation studies of ion temperature gradient driven turbulence which investigate the role of non-resonant modes in turbulence spreading, turbulence regulation, and self-generated plasma rotation. Non-resonant modes, which are those without a rational surface within the simulation domain, are identified as nonlinearly driven, radially extended convective cells. Even though the amplitudes of such convective cells are much smaller than that of the resonant, localized turbulence eddies, we find from bicoherence analysis that the mode-mode interactions in the presence of such convective cells increase the efficiency of turbulence spreading associated with nonlocality phenomena. Artificial suppression of the convective cells shows that turbulence spreading is reduced, and that the turbulence intensity profile is more localized. The more localized turbulence intensity profile produces stronger Reynolds stress and E Multiplication-Sign B shear flows, which in turn results in more effective turbulence self-regulation. This suggests that models without non-resonant modes may significantly underestimate turbulent fluctuation levels and transport.

Authors:
; ;  [1];  [1];  [2]
  1. National Fusion Research Institute, Eoeun-dong, Yuseong-gu, Daejeon 305-333 (Korea, Republic of)
  2. (United States)
Publication Date:
OSTI Identifier:
22068894
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 19; Journal Issue: 11; Other Information: (c) 2012 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; AMPLITUDES; CONVECTION; EFFICIENCY; FLUCTUATIONS; INTERACTIONS; ION TEMPERATURE; MODE RATIONAL SURFACES; NONLINEAR PROBLEMS; PLASMA SIMULATION; REYNOLDS NUMBER; ROTATING PLASMA; TEMPERATURE GRADIENTS; TURBULENCE

Citation Formats

Yi, S., Kwon, J. M., Rhee, T., Diamond, P. H., and Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429. Effect of secondary convective cells on turbulence intensity profiles, flow generation, and transport. United States: N. p., 2012. Web. doi:10.1063/1.4767652.
Yi, S., Kwon, J. M., Rhee, T., Diamond, P. H., & Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429. Effect of secondary convective cells on turbulence intensity profiles, flow generation, and transport. United States. doi:10.1063/1.4767652.
Yi, S., Kwon, J. M., Rhee, T., Diamond, P. H., and Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429. Thu . "Effect of secondary convective cells on turbulence intensity profiles, flow generation, and transport". United States. doi:10.1063/1.4767652.
@article{osti_22068894,
title = {Effect of secondary convective cells on turbulence intensity profiles, flow generation, and transport},
author = {Yi, S. and Kwon, J. M. and Rhee, T. and Diamond, P. H. and Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429},
abstractNote = {This paper reports the results of gyrokinetic simulation studies of ion temperature gradient driven turbulence which investigate the role of non-resonant modes in turbulence spreading, turbulence regulation, and self-generated plasma rotation. Non-resonant modes, which are those without a rational surface within the simulation domain, are identified as nonlinearly driven, radially extended convective cells. Even though the amplitudes of such convective cells are much smaller than that of the resonant, localized turbulence eddies, we find from bicoherence analysis that the mode-mode interactions in the presence of such convective cells increase the efficiency of turbulence spreading associated with nonlocality phenomena. Artificial suppression of the convective cells shows that turbulence spreading is reduced, and that the turbulence intensity profile is more localized. The more localized turbulence intensity profile produces stronger Reynolds stress and E Multiplication-Sign B shear flows, which in turn results in more effective turbulence self-regulation. This suggests that models without non-resonant modes may significantly underestimate turbulent fluctuation levels and transport.},
doi = {10.1063/1.4767652},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 11,
volume = 19,
place = {United States},
year = {2012},
month = {11}
}