Divertor II for ASDEX Upgrade

Divertor II, scheduled for early 1997, combines improved divertor physics with high configurational flexibility. Density control, comparable to the predecessor Divertor I, requires the addition of a cryopump with a nominal pumping speed of 100 m³/s. Three target plate configurations are envisaged, which will be assessed consecutively: the LYRE, GAS BAG 1 and GAS BAG 2. All of them can be equipped in the private flux region either with a roof baffle or a septum. In March 1995 Divertor II received EURATOM preferential support, and manufacturing of the LYRE and the cryopump was started then. This paper describes the Divertor II configurations, in particular the LYRE with cryopump and the underlying design principles