A study of JET carbon impurity sources

This paper compares experimental JET carbon and hydrogen visible emission to EDGE2D/NIMBUS calculations. The calculations themselves indicate that: (1) the integrated deuterium ionization in the SOL is proportional to the Dα chordal integrated photon flux, (2) the carbon ionization in the SOL or the divertor is proportional to the calculated CIII chordal light, and (3) the ratio of line integrated photon fluxes from a vertical chord to a horizontal chord indicates whether the main chamber SOL content originated primarily from a wall source or from ion flow out of the divertor. Comparison was made to both inter-ELM H-Mode and L-Mode JET gas box divertor plasmas. The calculations infer that the experimental core contamination was caused by carbon sputtering arising primarily from the main chamber. The experimental, main chamber carbon yield was 1–4% in L-Mode and 5–10% in the inter-ELM H-Mode period.