Material transport by erosion and redeposition on surface probes in the scrape-off layer of JET
The material transport by erosion and redeposition at the plasma facing wall areas in high temperature plasma experiments has been studied using limiter-like carbon probes with well defined surface deposits and depth markers. The probes have been exposed in the scrape-off layer (SOL) of JET during single discharges. For the evaluation of these experiments a computer program, ERO, has been developed. The calculated erosion-deposition rates for carbon as a function of the distance to the last closed flux surface agree well with the experimental results. For a single 4He JET discharge, erosion yields of 530 Angstrom for the silicon deposit and 80 Angstrom for vanadium have been measured near the LCFS. A large amount of redeposited silicon (about 17 % of the sputtered atoms) has been found on the probe surface in co-deposition with carbon on an area not favoured by the proposed model. This observation can be explained by an additional force on the impurity ions (for example the existence of a local electric field), which may cause the deposition.
Bibliographic Reference: Article: Nuclear Fusion, Vol. 33 (1993) No. 4, pp. 581-589
Record Number: 199311139 / Last updated on: 1994-11-29
Original language: en
Available languages: en