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P: Fachverband Plasmaphysik

P 5: Magnetic Confinment Fusion/HEPP III

P 5.4: Vortrag

Dienstag, 1. April 2025, 12:20–12:35, ZHG102

Investigation of Density-Potential Coupling as Agent for the Interplay of Particle and Momentum Transport in Drift Wave Turbulence — •Ralph Sarkis, Bernhard Schmid, Günter Tovar, and Mirko Ramisch — IGVP, University of Stuttgart, Germany

The experimental investigation of turbulent transport dynamics in the edge of magnetically confined plasmas highlights the coupling of density and potential fluctuations in the interplay of particle and momentum transport. At the TJ-K stellarator, a poloidal Langmuir-probe array is set up to simultaneously measure density and potential fluctuations, providing spatiotemporal observations of particle transports and Reynolds stress. While both transport phenomena rely on con- flicting density-potential coupling conditions, experimental measurements exhibit a shared local region of maximum levels. Dynamics investigations reveal an inverse temporal relation of particle and momentum transport, substantiated by their strong correlation and anti-correlation with the density-potential decoupling, respectively. The spectral decomposition of the coupling parameter emphasizes the role of small-scale contributions in the drift-wave dominated transports' formation. Furthermore, the occurrence of zonal flows appears to alter the transports' dependence on the coupling. Both particle and momentum transport appear to be decorrelated from the density-potential coupling during zonal flows. This phenomenon is elucidated by analyses of spectral energy transfer between small-scale fluctuations in density and potential and meso-scale shear flows.