OEDGE modeling of far-SOL tungsten impurity sources and screening in WEST. (October 2022)

• Record Type: Journal Article
• Authors: Maeker, J.B.; Nichols, J.H.; Donovan, D.C.; Grosjean, A.; Gunn, J.; Fedorczak, N.; Guillemaut, C.; Klepper, C.C.; Unterberg, E.A.; Easley, D.C.; Team, WEST
• Is Part Of: Nuclear materials and energy. Volume 33(2022)
• Publication Date: 2022-10
• Subjects: WEST -- Tungsten impurity modeling -- Scrape-off layer -- Impurity screening -- Far-SOL; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2022.101309
• Languages: English
• ISSNs: 2352-1791

Abstract

Abstract: The plasma background and impurity transport in the scrape-off layer (SOL) of the WEST tokamak are modeled for three discharges over a Psep power scan ranging between 1.5 and 2.35 MW. An extended modeling grid is used to investigate far-SOL sourcing from the WEST baffle and lower divertor. Divertor Langmuir probe data at the targets and upstream data from reciprocating Langmuir probes and interferometry/reflectometry is used to create a simulated background plasma with the OSM and EIRENE codes. W-I spectroscopic data from WEST at the lower divertor and baffle is used to estimate the sputtered W flux as an input to the impurity transport code DIVIMP. A potential mechanism for far-SOL impurities from the baffle to transport into the near-SOL is proposed and discussed in terms of the model's force balances. Analysis of simulated impurity transport showed similar impurity density at the separatrix for the mid and high-power cases despite the high-power case having 10% more sputtered W. This is explained by the combination of differing trends in the sourcing and screening with scaling power.