A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity

Nespoli, Federico; Tamain, Patrick; Fedorczak, Nicolas; Galassi, Davide; Marandet, Yannick

doi:10.1088/1741-4326/ab6f1e

Title: A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity

Journal Article · 19 February 2020 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/ab6f1e · OSTI ID:1595813

^[1]; Tamain, Patrick ^[2];

^[2]; Galassi, Davide ^[3]; Marandet, Yannick ^[4]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
CEA Cadarache, St. Paul-lez-Durance (France). IRFM
École Polytechnique Fédérale de Lausanne (EPFL) (Switzerland). Swiss Plasma Center (SPC)
Aix Marseille Univ. (France)

Plasma filaments generated by turbulence in the scrape-off layer are sometimes observed in experiments and simulations to disconnect from the target plate in the vicinity of the X-point, resulting in a ‘quiescent zone’ with reduced fluctuations, possibly affecting the fluctuating part of the divertor heat loads. This phenomena is usually explained by the flux tubes squeezing, induced by flux expansion, down to scales where collisions dominate. In this work, we consider an additional mechanism spontaneously arising at the X-point: the poloidal shear in radial E × B velocity. Through a simple model, tested against 3D global turbulence simulations, herein we quantify the effectiveness of this disconnection mechanism and identify ways to control it.

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Research Organization:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: European Commission; USDOE

Grant/Contract Number:: AC02-09CH11466

OSTI ID:: 1595813

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 4 Vol. 60; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Title: A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity

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