Journal Article

FZJ-2020-01922

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Impact of divertor configuration on recycling neutral fluxes for ITER-like wall in JET H-mode plasmas

de la Cal, E. (Corresponding author) ; Losada, U. ; de Aguilera, A. M. ; Shaw, A. ; Solano, E. ; Alegre, D. ; Balboa, I. ; Carvalho, P. ; Gaspar, J. ; Borodkina, I. ; Brezinsek, S.FZJ* ; Douai, D. ; Giroud, C. ; Guillemaut, C. ; Hidalgo, C.FZJ* ; Huber, A.FZJ* ; Joffrin, E. ; Loarer, T. ; de la Luna, E. ; Manzanares, A. ; Militello, F. ; de Pablos, L. ; Wiesen, S.FZJ*

2020
IOP Publ. Bristol

This record in other databases:    

Please use a persistent id in citations: http://hdl.handle.net/2128/25121  doi:10.1088/1361-6587/ab5fb1

Abstract: In recent years it has been well known that in JET, with the ITER-like wall, the performance of high-power H-mode plasmas depends strongly on the magnetic topology of the divertor. This is generally attributed to the effect of the magnetic field shaping on the neutral flux transport and pumping, which—in high density H-mode plasmas—determine the pedestal properties and the global confinement. In this work we have analysed the spatial distribution and the dynamic behaviour of the D α -emission for different magnetic configurations. Experimental observations indicate that for certain configurations, the surface temperature and the D α —emission anomalously increase on top of the inner divertor, which points to thermal outgassing there. This is also the region where most beryllium co-deposits accumulate and most deuterium becomes trapped. The overheating at this region far from the strike point (SP) is observed to happen in magnetic configurations with reduced distance between the divertor material surface and the separatrix (clearance). The neutral flux that appears at the upper inner divertor during a few milliseconds after the ELM-crash, is more than an order of magnitude larger than the gas puffing rate and dominates over all other regions. Finally, a preliminary study describes how this thermal fuel outgassing from the co-deposited layers could be used intentionally as a wall-conditioning in JET technique with plasmas that focus their particle and heat flux there. This could be used as a complementary wall isotope control technique and more specifically for tritium recovery from the upper inner divertor where most fuel-trapping beryllium co-deposits accumulate in JET ITER-like wall.

---

Contributing Institute(s):

1. Plasmaphysik (IEK-4)

Research Program(s):

1. 174 - Plasma-Wall-Interaction (POF3-174) (POF3-174)

Appears in the scientific report 2020

---

Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

---