Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology

Perseo, Valeria; Effenberg, F.; Gradic, D.; König, R.; Ford, O. P.; Reimold, F.; Ennis, D. A.; Schmitz, O.; Sunn Pedersen, T.

doi:10.1088/1741-4326/ab4320

Title: Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology

Journal Article · 26 September 2019 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/ab4320 · OSTI ID:1572710

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^[1]; König, R. ^[1]; Ford, O. P. ^[1]; Reimold, F. ^[1]; Ennis, D. A. ^[3]; Schmitz, O. ^[4];

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Max-Planck-Institut für Plasmaphysik, Greifswald (Germany)
Univ. of Wisconsin, Madison, WI (United States); Princeton Univ., NJ (United States)
Auburn Univ., Auburn, AL (United States)
Univ. of Wisconsin, Madison, WI (United States)

We report on the first experimental verification of theoretically predicted multiple bundles of counter-streaming plasma flows in the island-divertor scrape-off layer (SOL) of the stellarator Wendelstein 7-X. In the standard toroidal field direction (counter-clockwise when looking from the top) experiments, the overall structure of the SOL flows, such as flow directions, the number of flow bundles and the magnitude of the flow velocities, are consistent with numerical predictions obtained with EMC3-EIRENE. However, the modelling does not predict changes of the flow patterns with reversal of the magnetic field direction, which are experimentally observed. This indicates that additional relevant physics, such as particle drifts, will need to be incorporated into the numerical model to better describe the whole stellarator scrape-off layer behaviour.

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

Sponsoring Organization:: USDOE

Contributing Organization:: the W7-X Team

Grant/Contract Number:: SC0014529; SC0014210

OSTI ID:: 1572710

Journal Information:: Nuclear Fusion, Vol. 59, Issue 12; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 15 works

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Title: Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology

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