Speaker
Dr
Federico Nespoli
(Aix-Marseille Universite)
Description
First experimental results show the achievement of a variety of diverted configurations in WEST [1], which features a full tungsten divertor that will undergo heat fluxes of the same magnitude as for the ITER divertor [2]. The transport code SolEdge2D-EIRENE [3] has been used extensively in the past both in support of the WEST design [4] and campaign planning [5], and to model the first experimental results.
The turbulence code TOKAM3X [6] is here used for the first time to model the plasma turbulence in the edge and scrape-off layer of WEST. TOKAM3X allows to model the 3D evolution of turbulence in a realistic magnetic geometry, featuring one or more X-points. We compare in particular two configurations, a standard single-null case featuring a secondary X-point at the top of the plasma, and a “shallow divertor” configuration, where the main X-point is located at the divertor plate.
The influence of the divertor configuration on transport and the steady state profiles is discussed. The effect of the presence of the two X-points on turbulence is studied through the application of a blob detection and tracking technique, here presented, allowing to resolve the temporal evolution of the 3D shape of the filaments.
The results from the blob tracking technique are compared with a conditional average sampling analysis, commonly used in experiments. The blob sizes and velocities obtained from both techniques are compared with existing scaling laws. This comparison, together with a cross-correlation analysis, indicates that the presence of the two X-points helps in disconnecting the low field side midplane blobs from both the divertor leg and the high field side of the tokamak.
[1] M. Goniche et al, “First LHCD experiments in WEST”, 45th EPS Conference, Prague 2018
[2] C. Bourdelle et al., Nucl. Fusion 55 (2015) 063017
[3] H. Bufferand et al., Contrib. Plasma Phys. 56 (2016) 555 562 [4] H. Bufferand et al. Nucl. Fusion 55 (2015) 053025 [5] G. Ciraolo et al., Nuclear Material and Energy 12 (2017) 187-192 [6] P. Tamain et al., Journal of Computational Physics 321 (2016) 606623
Primary author
Dr
Federico Nespoli
(Aix-Marseille Universite)
Co-authors
Dr
Davide Galassi
(Aix-Marseille Université)
Dr
Eric Serre
(Aix-Marseille Université)
Dr
Guido Ciraolo
(CEA)
Dr
Hugo Bufferand
(CEA)
Dr
Nicolas Fedorczak
(CEA)
Dr
Patrick Tamain
(CEA)
Dr
Philippe Ghendrih
(CEA)
