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Turbulence Interaction with Driven Transport Barriers in the Scrape‐Off Layer of Tokamaks
Author(s) -
Nace N.,
Perin M.,
Tamain P.,
Ciraolo G.,
Baudoin C.,
Futtersack R.,
Ghendrih Ph.,
Norscini C.
Publication year - 2016
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201610052
Subject(s) - turbulence , intermittency , shear (geology) , mechanics , tokamak , physics , materials science , plasma , quantum mechanics , composite material
Two mechanisms able to generate a transport barrier by the stabilization of turbulence are analysed: the radial shear of the E × B velocity and the radial gradient of this shear. These two mechanisms are artificially forced in dedicated 2D non‐linear fluid simulations to study their impact on turbulence in the Scrape‐Off Layer. Generated barriers are characterized by their turbulence stopping capability and a key parameter, the barrier efficiency, is pointed out. The first two moments of this criterion can be studied to quantify the global efficiency, shape and width of the barrier as well as its intermittency. It is found that both mechanisms can drive intermittent or stable barriers but the radial shear mechanism generates stronger relaxation events. Small scale structures are damped by the E × B velocity shear while the radial shear gradient acts mainly on large scales. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)