Abstract
Nitrogen has been introduced in H-mode plasmas in JET in order to study its radiation cooling capability and impact on the erosion of divertor plasma-facing components made of carbon-fiber composites (CFC). Experiments in the ionizing plasma regime with low nitrogen injection show a reduction of the total carbon erosion in the divertor measured with the aid of optical spectroscopy on C+. Though chemical sputtering by nitrogen takes place, identified by the appearance of CN B-X band emission, the additional carbon source is overcompensated by a reduction of regular sputtering by deuterium bombardment. Moderate plasma cooling associated with reduction of the sputtering yield and dilution of the CFC surface by nitrogen can be attributed to the favorable reduction of the carbon source.
| Original language | English |
|---|---|
| Pages (from-to) | 624-628 |
| Number of pages | 5 |
| Journal | Journal of Nuclear Materials |
| Volume | 417 |
| Issue number | 1-3 |
| DOIs | |
| State | Published - Oct 1 2011 |
| Externally published | Yes |
Funding
The authors would like to thank F.L. Tabares for the fruitful discussion about nitrogen chemistry in laboratory plasmas. This work, supported by the European Communities under the contract of Association between EURATOM/FZJ, was carried out within the framework of the European Fusion Development Agreement. The views and opinions expressed herein do not necessarily reflect those of the European Commission.
