ASDEX Upgrade Team(1990). ASDEX Contributions to the 9th International Conference on Plasma Surface Interaction in Controlled Fusion Devices (Bournemouth, England, May 21-25, 1990) and Workshop on "Relevance, realization and stability of a cold layer at the edge for fusion reactors" (Cadarache, France, May 28-30, 1990) (IPP III/163). Garching (DE): Max-Planck-Institut für Plasmaphysik.