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P: Fachverband Plasmaphysik

P 18: Poster: Theorie/Modellierung

P 18.13: Poster

Mittwoch, 1. April 2009, 17:30–19:30, Foyer des IfP

Time Series Analysis of Gyrokinetic Turbulence Data — •Holger Angenent¹, Frank Jenko², and Rudolf Friedrich¹ — ¹Institut für Theoretische Physik, WWU Münster, Germany — ²Max-Planck-Institut für Plasmaphysik, D-85748 Garching, Germany

Time series of gyrokinetic computations near critical ion temperature gradients show heavy fluctuations. A characterization of such data - in particular with respect to stationarity - under these circumstances is non-trivial. These parameter regimes are of significant relevance for tokamaks, however, whose gradients are close to the threshold of ion temperature gradient (ITG) modes. The time series, which are generated with the GENE code (www.ipp.mpg.de/∼fsj/gene), are analyzed with respect to a criterion for stationarity and a basic mechanism describing a bifurcation related to the so-called Dimits upshift.
As a more simple model, a two dimensional fluid model is used. It shows the basic patterns in plasma turbulence. Theses are zonal flows for the case of ion temperature gradient driven turbulence (ITG), respectively streamers for electron temperature gradient driven turbulence (ETG). The influence of the patterns regarding the transport properties of massless tracer particles is investigated and compared with the GENE data.