Spectroscopic measurements in the DIII-D lower divertor have shown an order of magnitude decrease in the brightness of the CD emission band over the course of eight years of plasma discharges. These observations could imply a reduction of the chemical erosion of the carbon component in the divertor. To test this hypothesis, chemical erosion measurements of specimens from the DIII-D lower divertor inner and outer strike points were performed using a low-energy D2+ ion beam, with energies extending down to ∼15 eV/D+. The results indicate that the erosion characteristics of the DIII-D lower divertor plasma-exposed specimens are similar to those of pyrolytic graphite and the virgin DIII-D tile material. The total chemical erosion yields for all specimens peak at ∼2-4% at 700 K for 15 eV/D+, and reach ∼7% for 200 eV/D+. © 2004 Elsevier B.V. All rights reserved.
Wright, G. M., Haasz, A. A., Davis, J. W., & MacAulay-Newcombe, R. G. (2005). Chemical erosion of DIII-D lower divertor tiles. In Journal of Nuclear Materials (Vol. 337–339, pp. 74–78). https://doi.org/10.1016/j.jnucmat.2004.10.009