Authors: P. Wurz and A.H. Gabriel
Reference: SOHO 8 Workshop Proceedings, Plasma Dynamics and Diagnostics in the Solar Transition Region and Corona, ESA SP-446, 87-95, 1999.
The topic of this working group was divided in four subtopics with the titles: i) Coronal hole structures, ii) Polar plumes: Is there a two-component plasma in the holes? iii) Fast wind acceleration region, and iv) Origin of slow solar wind. The first two points were discussed virtually together during the working group sessions. In this review we reversed the order of these points, since the question of the two-component plasma in coronal holes has to be addressed to proceed with the structure of the coronal holes.