DIVERTOR GEOMETRY OPTIMIZATION FOR ASDEX UPGRADE

One of the critical questions to be solved for ITER (or any other reac tor) is the power exhaust problem (compatible with particle exhaust). Optimized diverters have to be tested in existing geometries based mai nly on the idea of closing them Very efficiently to the main chamber a nd, by the choice of the plate and baffle geometry, positively influen cing the flow pattern of hydrogen favoring good impurity entrainment. Also, for ASDEX Upgrade there is an experimental necessity for an impr oved divertor due to the increased heating power (24 MW will be availa ble from 1997 on compared to the present Is MW). We present the optimi zation strategy for the divertor II of ASDEX Upgrade, using elaborate numerical models and codes (B2-Eirene) as well as simple models. We st art with the choice of a proper target plate geometry, and then furthe r discuss how main chamber and private flux baffling will be done, and how this affects neutral recirculation pattern and pumping properties . For the final configuration the impurity entrainment properties are analyzed.