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Title: The energetic coupling of scales in gyrokinetic plasma turbulence

In magnetized plasma turbulence, the couplings of perpendicular spatial scales that arise due to the nonlinear interactions are analyzed from the perspective of the free-energy exchanges. The plasmas considered here, with appropriate ion or electron adiabatic electro-neutrality responses, are described by the gyrokinetic formalism in a toroidal magnetic geometry. Turbulence develops due to the electrostatic fluctuations driven by temperature gradient instabilities, either ion temperature gradient (ITG) or electron temperature gradient (ETG). The analysis consists in decomposing the system into a series of scale structures, while accounting separately for contributions made by modes possessing special symmetries (e.g., the zonal flow modes). The interaction of these scales is analyzed using the energy transfer functions, including a forward and backward decomposition, scale fluxes, and locality functions. The comparison between the ITG and ETG cases shows that ETG turbulence has a more pronounced classical turbulent behavior, exhibiting a stronger energy cascade, with implications for gyrokinetic turbulence modeling.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [3] ;  [2]
  1. Applied Mathematics Research Centre, Coventry University, Coventry CV1 5FB (United Kingdom)
  2. (Germany)
  3. Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22299814
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 7; Other Information: (c) 2014 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; COMPARATIVE EVALUATIONS; ELECTRON TEMPERATURE; ELECTRONS; ENERGY TRANSFER; FLUCTUATIONS; FREE ENERGY; NONLINEAR PROBLEMS; PLASMA; PLASMA SIMULATION; SYMMETRY; TEMPERATURE GRADIENTS; TURBULENCE; WASTE HEAT UTILIZATION