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3D structure and dynamics of filaments in turbulence simulations of WEST diverted plasmas

Authors :
Ph. Ghendrih
Nicolas Fedorczak
Davide Galassi
Eric Serre
G. Ciraolo
Yannick Marandet
F. Nespoli
Patrick Tamain
Raffaele Tatali
Hugo Bufferand
Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2)
Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Institut de Recherche sur la Fusion par confinement Magnétique (IRFM)
Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Physique des interactions ioniques et moléculaires (PIIM)
Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)
Serre, Eric
Source :
Nuclear Fusion, Nuclear Fusion, 2019, Nuclear Fusion, IOP Publishing, 2019
Publication Year :
2019
Publisher :
HAL CCSD, 2019.

Abstract

International audience; We study the effect of a diverted magnetic geometry on edge plasma turbulence, focusing on the three-dimensional structure and dynamics of filaments, also called blobs, in simulations of the WEST tokamak, featuring a primary and secondary X-point. For this purpose, in addition to classical analysis techniques, we apply here a novel fully 3D Blob Recognition And Tracking (BRAT) algorithm, allowing for the first time to resolve the three-dimensional structure and dynamics of the blobs in a turbulent 3D plasma featuring a realistic magnetic geometry. The results are tested against existing theoretical scalings of blob velocity [Myra et al, Physics of Plasmas 2006]. The complementary analysis of the 3D structure of the filaments shows how they disconnect from the divertor plate in the vicinity of the X-points, leading to a transition from a sheath-connected regime to the ideal-interchange one. Furthermore, the numerical results show non-negligible effects of the turbulent background plasma: approximately half of the detected filaments are involved in mutual interactions, eventually resulting in negative radial velocities, and a fraction of the filaments is generated by turbulence directly below the X-point.

Details

Language :
English
ISSN :
00295515, 17414326, and 07413335
Database :
OpenAIRE
Journal :
Nuclear Fusion, Nuclear Fusion, 2019, Nuclear Fusion, IOP Publishing, 2019
Accession number :
edsair.doi.dedup.....b1d722773173894e75fcef98a1a49b00