Erlangen 2026 – scientific programme

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P: Fachverband Plasmaphysik

P 16: Poster Session Plasma Physics

P 16.87: Poster

Thursday, March 19, 2026, 13:45–15:45, Redoutensaal

On the role of density-potential coupling in the interplay of zonal-flow and intermittency formation — •Lilian Harumi Yoshida, Mirko Ramisch, and Ralph Sarkis — IGVP, University of Stuttgart, Germany

The destabilization of density perturbations in drift-wave turbulence is based on the decoupling of density (ñ) and potential (φ) fluctuations. This decoupling mechanism is promoted by electron collisionality, which in turn tends to change the turbulent behaviour from adiabatic into a hydrodynamic one, where density becomes passively advected and resembles the intermittent vorticity. Decoupling is also intrinsic to the interchange drive of filamentary, intermittent density structures - so-called blobs - in the scrape-off layer (SOL). In contrast to blobs, strong coupling is essential for the Reynolds-stress drive of zonal-flows (ZF). However, recent studies showed a causal link between blob detachment from the bulk plasma and ZF generation inside the separatrix. In this experimental work, multiple Langmuir-probe arrays are used at the TJ-K stellarator to untangle the interplay of ñ−φ coupling with ZF and intermittency formation. Conditional sampling reveals a temporal correlation between net turbulent particle flux and zonal intermittency levels, which is in-line with the associated drift-wave destabilization. Furthermore, the coupling and intermittency dynamics across the separatrix is examined, shedding light on the role of blobs in ZF formation.