Berlin 2014 – scientific programme

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P: Fachverband Plasmaphysik

P 14: Poster Session - Theory and Modelling

P 14.11: Poster

Tuesday, March 18, 2014, 16:30–18:30, SPA Foyer

Numerical simulations of drift wave-zonal flow turbulence — •Ole Meyer¹, Odd Erik Garcia², Ralph Kube², and Alexander Kendl¹ — ¹University of Innsbruck, Institute for Ion Physics and Applied Physics, A-6020 Innsbruck, Austria — ²University of Tromsø, Department of Physics and Technology, N-9037 Tromsø, Norway

In the edge of magnetically confined plasmas one experimentally observes long-range correlations in time series of fluctuating plasma parameters. This is believed to be indirect evidence of self- organized criticality behavior of the radial particle flux. A well established model that describes plasma edge dynamics is given by the Hasegawa Wakatani equations (HW). The HW model can be modified (MHW) to allow for self-consistent formation of zonal structures from the underlying drift-wave turbulence. A Fourier-Galerkin method is used to solve the MHW equations in a two-dimensional slab geometry, assuming a uniform and constant magnetic field. Simulations of the quasi-adiabatic regime of the MHW model have been performed well into the non-linearly saturated state. Time series from these simulations are analysed statistically using rescaled range (R/S) analysis and temporal structure functions. Probability distributions (PDFs) of fluctuating quantities are essentially Gaussian for coupling- parameter C = 0.1 and C = 0.2 whereas increased adiabacity (C = 1) yields exponential tails in PDFs. R/S and temporal structure function analysis computes Hurst exponents close to 0.5. Non-linear scaling exponents in structure functions give evidence of multi-fractal behavior in fluctuating quantities.