Nuclear Materials and Energy (Oct 2022)

OEDGE modeling of far-SOL tungsten impurity sources and screening in WEST

  • J.B. Maeker,
  • J.H. Nichols,
  • D.C. Donovan,
  • A. Grosjean,
  • J. Gunn,
  • N. Fedorczak,
  • C. Guillemaut,
  • C.C. Klepper,
  • E.A. Unterberg,
  • D.C. Easley,
  • WEST Team

Journal volume & issue
Vol. 33
p. 101309

Abstract

Read online

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.

Keywords