ASDEX

In Europe, DITE at Culham, UK and ASDEX at Garching, FRG are the only experiments in which the divertor concept of impurity control is being tested. ASDEX (Axially Symmetric Divertor EXperiment) employs a poloidal divertor in which the total poloidal flux outside the plasma is diverted, i.e. charged particles reach the divertor along field lines after a few revolutions around the major circumference. This scheme thus guarantees a short path for particle transport into the divertor and also preserves the axisymmetry of the tokamak configuration. In order to be able to assess the improvements in plasma purity by the divertor, the magnetic field configuration of ASDEX is designed in such a way that diverted and undiverted plasmas of equal size and cross-section can be compared. (Auth.)