Velocity shear, turbulent saturation, and steep plasma gradients in the scrape-off layer of inner-wall limited tokamaks

Halpern, Federico D.; Ricci, Paolo

doi:10.1088/1741-4326/aa4eb6

Title: Velocity shear, turbulent saturation, and steep plasma gradients in the scrape-off layer of inner-wall limited tokamaks

Journal Article · Mon Dec 19 00:00:00 EST 2016 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aa4eb6· OSTI ID:1345664

Halpern, Federico D. ^[1]; Ricci, Paolo ^[2]

Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); General Atomics, San Diego, CA (United States)
Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland)

The narrow power decay-length (λ_q), recently found in the scrape-off layer (SOL) of inner wall limited (IWL) discharges in tokamaks, is studied using 3D, flux-driven, global two fluid turbulence simulations. The formation of the steep plasma profiles is found to arise due to radially sheared E×B poloidal flows. A complex interaction between sheared flows and parallel plasma currents outflowing into the sheath regulates the turbulent saturation, determining the transport levels. We quantify the effects of sheared flows, obtaining theoretical estimates in agreement with our non-linear simulations. As a result, analytical calculations suggest that the IWL λ_q is roughly equal to the turbulent correlation length.

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Research Organization:: Computational Simulation Centre of International Fusion Energy Research Centre (IFERC-CSC), Aomori (Japan)

Sponsoring Organization:: USDOE

Grant/Contract Number:: FC02-04ER54698

OSTI ID:: 1345664

Journal Information:: Nuclear Fusion, Vol. 57, Issue 3; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 21 works

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References (22)

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Cited By (8)

Poloidal asymmetry in the narrow heat flux feature in the TCV scrape-off layer Tsui, C. K.; Boedo, J. A.; Halpern, F. D. Physics of Plasmas, Vol. 24, Issue 6 https://doi.org/10.1063/1.4985075	journal	June 2017
Three-dimensional simulations of plasma turbulence in the RFX-mod scrape-off layer and comparison with experimental measurements Riva, Fabio; Vianello, Nicola; Spolaore, Monica Physics of Plasmas, Vol. 25, Issue 2 https://doi.org/10.1063/1.5008803	journal	February 2018
Impurity seeding for suppression of the near scrape-off layer heat flux feature in tokamak limited plasmas Nespoli, F.; Labit, B.; Furno, I. Physics of Plasmas, Vol. 25, Issue 5 https://doi.org/10.1063/1.5023201	journal	May 2018
Shaping effects on scrape-off layer plasma turbulence: A rigorous validation of three-dimensional simulations against TCV measurements Riva, F.; Tsui, C. K.; Boedo, J. A. Physics of Plasmas, Vol. 27, Issue 1 https://doi.org/10.1063/1.5123451	journal	January 2020
Blob properties in full-turbulence simulations of the TCV scrape-off layer Nespoli, F.; Furno, I.; Labit, B. Plasma Physics and Controlled Fusion, Vol. 59, Issue 5 https://doi.org/10.1088/1361-6587/aa6276	journal	March 2017
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Impurity seeding for suppression of the near Scrape-Off Layer heat flux feature in tokamak limited plasmas Nespoli, F.; Labit, B.; Furno, I. arXiv https://doi.org/10.48550/arxiv.1712.00951	text	January 2017

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