Particle collection at the plasma edge by a fast reciprocating probe at the TEXTOR tokamak
2003 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 313, 729-733 p.Article in journal (Refereed) Published
A fast reciprocating probe system capable of transferring different types of heads has been constructed and implemented at the TEXTOR tokamak for diagnosing the plasma edge. It gives the possibility of using a particle collector technique to extend studies of material transport from the scrape-off layer to the near plasma edge. For the first time, the system was used for exposures of graphite samples (pure and coated with a-C:H or W) at positions both within and outside the last closed flux surface. Various surface analysis methods were applied to investigate the probe morphology and, by this, to determine radial deposition profiles of boron impurities and deuterium. The profiles for boron are remarkably flat whilst those for deuterium are characterised by a steep decay with the e-folding length of approximately 15 mm. On tungsten-coated samples almost no deuterium was found, most likely because of little carbon co-deposition, shallow implantation and low trapping coefficient of deuterons in the tungsten layer. Reconstruction of experimental results by means of a multifluid TECXY code helped to identify the contribution of impurity sources (limiters, wall) to the observed radial distribution of species.
Place, publisher, year, edition, pages
2003. Vol. 313, 729-733 p.
collector probe, erosion, deposition, impurity fluxes, plasma edge, TEXTOR, electric-field, transport, limiters, fluxes, layer
IdentifiersURN: urn:nbn:se:kth:diva-22412ISI: 000182146700134OAI: oai:DiVA.org:kth-22412DiVA: diva2:341110
QC 201005252010-08-102010-08-10Bibliographically approved