221 articles  [english version]
 HAL : hal-00002004, version 1
 Diffusivity induced by vortex-like coherent structures in reversed field pinch plasmas
 Monica Spolaore 1, Vanni Antoni 1
 (14/06/2004)
 Coherent structures emerging from the background turbulence have been detected by electrostatic measurements in the edge region of two Reversed Field Pinch experiments, RFX (Padua) and Extrap-T2R (Stockholm). Measurements have been performed by arrays of Langmuir probes which allowed simultaneous measurements of temperature, potential and density to be carried out. These structures have been interpreted as a dynamic balance of dipolar and monopolar vortices, whose relative population are found to depend on the local mean $E\times B$ flow shear. The contribution to the anomalous transport of these structures has been investigated and it has been found that the corresponding diffusion coefficient accounts up to 50% of the total diffusivity. The experimental findings indicate that the diffusion coefficient associated to the coherent structures depends on the relative population of the two types of vortices and is minimum when the two populations are equal. An interpretative model is proposed to explain this feature.
 1 : Consorzio RFX Associazione Euratom-ENEA sulla fusione 2 : Alfvén laboratory, Division of Fusion Plasma Physics Royal Institut of Technology – Association Euratom/VR 3 : ENEA FRASCATI Associazione Euratom-ENEA sulla fusione
 Domaine : Physique/Physique/Physique des plasmas
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 hal-00002004, version 1 http://hal.archives-ouvertes.fr/hal-00002004 oai:hal.archives-ouvertes.fr:hal-00002004 Contributeur : Monica Spolaore <> Soumis le : Vendredi 22 Octobre 2004, 18:01:17 Dernière modification le : Vendredi 22 Octobre 2004, 22:02:09