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Title: Numerical investigation of frequency spectrum in the Hasegawa-Wakatani model

The wavenumber-frequency spectrum of the two-dimensional Hasegawa-Wakatani model is investigated in the hydrodynamic, intermediate, and adiabatic regimes. A nonlinear frequency and a line width related to energy transfer properties provide a measure of the average frequency and spectral broadening, respectively. In the adiabatic regime, narrow spectra, typical of wave turbulence, are observed with a nonlinear frequency shift in the electron drift direction. In the hydrodynamic regime, broad spectra with almost zero nonlinear frequencies are observed. Nonlinear frequency shifts are shown to be related to nonlinear energy transfer by vorticity advection through the high frequency region of the spectrum. In the intermediate regime, the nonlinear frequency shift for density fluctuations is observed to be weaker than that of electrostatic potential fluctuations. The weaker frequency shift of the density fluctuations is due to nonlinear density advection, which favors energy transfer in the low frequency range. Both the nonlinear frequency and the spectral width increase with poloidal wavenumber k{sub y}. In addition, in the adiabatic regime where the nonlinear interactions manifest themselves in the nonlinear frequency shift, the cross-phase between the density and potential fluctuations is observed to match a linear relation, but only if the linear response of the linearly stable eigenmodemore » branch is included. Implications of these numerical observations are discussed.« less
Authors:
 [1] ;  [2]
  1. Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of South Korea (Korea, Republic of)
  2. Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin, 53706 (United States)
Publication Date:
OSTI Identifier:
22218518
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 10; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ADVECTION; DRIFT INSTABILITY; ELECTRON DRIFT; ENERGY TRANSFER; FLUCTUATIONS; HYDRODYNAMICS; LINE BROADENING; LINE WIDTHS; NONLINEAR PROBLEMS; NUMERICAL ANALYSIS; PLASMA DENSITY; PLASMA DRIFT; POTENTIALS; TURBULENCE; TWO-DIMENSIONAL CALCULATIONS