Mainz 2022 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 19: Poster II

P 19.27: Poster

Donnerstag, 31. März 2022, 16:00–17:30, P

Causality analysis between turbulent phenomena across the separatrix at the TJ-K stellarator. — •Nicolas Dumérat, Bernhard Schmid, and Mirko Ramisch — IGVP, University of Stuttgart

The use of convergent cross-mapping (CCM) as a causality inference technique has proven its capacity for unveiling causal coupling between two variables measured in the same dynamical system. CCM describes a measure of how well the mapping - from a small region within a multidimensional phase space reconstruction in one variable (from time-delay embedding) - compares to the actual representation of the second variable in its reconstructed phase space.

Thus, CCM allows for the identification of causal links and direction of influence between variables and is extended to the study of plasma turbulence. In this frame, the causal relationship between various turbulent phenomena across the confinement region of the stellarator TJ-K is studied. The causal dependencies between blob generation and the zonal-flow - drift-wave system are investigated through Langmuir probe measurements. Using conditional averaging and bandwidth filtering, different spatial and temporal scales can be isolated and studied individually, allowing for fine causality analysis.