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Graphite probes were exposed in TEXTOR in order to collect neutral deuterium and neutral impurities which escape radially from the plasma. A flux of neutral deuterium of approx. 2 x 1.0 E14 D(0)/cm2/s at wall radius with typical energy in excess of approx. 400 eV can be inferred from retention in graphite. The corresponding deposition rate of boron was approx 3.7 x 1.0 E12 B(0)/cm2/s in conditions with fresh boronisation and a third of that with old boronisation. This is at least two orders of magnitude more than what is expected from a simple model of radial impurity transport which takes into account diffusion, electron impact ionisation and recombination, and parallel flow in the scrape-off layer. The large impurity deposition may have implications for the interpretation of collector probe experiments, inferring ion temperatures from Larmor radius effects.

Additional information

Authors: BERGSAKER H, Manne Siegbahn Institute of Physics, Stockholm (SE);EMMOTH B, Manne Siegbahn Institute of Physics, Stockholm (SE);WIENHOLD P, Institut für Plasmaphysik, Kernforschungsanlage Jülich GmbH, Jülich (DE)
Bibliographic Reference: Article: 18th European Conference on Controlled Fusion and Plasma Physics, Vol. III (1991) pp. 129-132
Record Number: 199111393 / Last updated on: 1994-12-02
Original language: en
Available languages: en