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

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

Journal Article · Thu Sep 26 00:00:00 EDT 2019 · Nuclear Fusion

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

^[1]; ^[2]; ^[1]; König, R. ^[1]; Ford, O. P. ^[1]; Reimold, F. ^[1]; Ennis, D. A. ^[3]; Schmitz, O. ^[4]; ^[1]

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.

View Accepted Manuscript (DOE)

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

Sponsoring Organization:: USDOE

Contributing Organization:: the W7-X Team

Grant/Contract Number:: SC0014210; SC0014529

OSTI ID:: 1572710

Alternate ID(s):: OSTI ID: 22930038

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

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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

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