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FLOW TOPOLOGY IN DRIFT-WAVE TURBULENCE

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A study of the relationship between Lagrangian statistics and flow topology in drift-wave turbulence is presented. The topology is characterized using the Okubo-Weiss criterion, which provides a conceptually simple tool to partition the flow into topologically different regions. The turbulent flow considered is governed by the Hasegawa-Wakatani description of drift-wave turbulence. This description has the particularity that it allows to study both Charney-Hasegawa-Mima dynamics and two-dimensional Navier-Stokes turbulence using the same equations by varying a control parameter which is called the adiabaticity. In different flow regimes, the probability density functions of residence time in the topologically different regions are computed using the Lagrangian Weiss field, i.e., the Weiss field along the particles trajectories. In elliptic and hyperbolic regions, the pdfs of the residence time have self-similar algebraic decaying tails. In contrast, in the intermediate regions the pdf has exponential decaying tails.

Author(s):

Diego del-Castillo-Negrete    
Oak Ridge National Laboratory
United States

Benjamin Kadoch    
IUSTI CNRS, ETIC, Aix-Marseille Université
France

W.J.T. Bos    
LMFA CNRS, Ecole Centrale de Lyon, Université de Lyon
France

Kai Schneider    
M2P2 CNRS and CMI, Aix-Marseille Université
France