Erosion and migration of tungsten employed at the central column heat shield of ASDEX Upgrade
In ASDEX Upgrade, tungsten was employed as plasma facing material at the central column heat shield in the plasma main chamber. The campaign averaged tungsten erosion flux was determined by measuring the difference of the W-layer thickness before and after the experimental campaign using ion beam analysis methods. The observed lateral variation and the total amount of eroded tungsten are attributed to erosion by impact of ions from the scrape-off layer plasma. Migration and re-deposition of eroded tungsten were investigated by quantitative analysis of deposited tungsten on collector probes and wall samples. The obtained results, as well as the spectroscopically observed low tungsten plasma penetration probability, indicate that a major fraction of the eroded tungsten migrates predominantly through direct transport channels in the outer plasma scrape-off layer without entering the confined plasma.
Bibliographic Reference: An article published in: Journal of Nuclear Materials, Volumes 307-311, Part 1, December 2002, Pages 139-143
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/10.1016/S0022-3115%2802%2901032-2
Record Number: 200316334 / Last updated on: 2003-06-09
Original language: en
Available languages: en