Modeling of the dynamic ergodic divertor of TEXTOR-94

A Dynamic Ergodic Divertor (DED) is under construction for TEXTOR-94. The e rgodization will be achieved by a set of 16 in-vessel perturbation - plus t wo compensation - coils located at the high field side of TEXTOR-94. The co ils follow helically the resonant magnetic field lines for one toroidal tur n and are individually fed outside the vessel allowing a large flexibility for possible connections, The DED-system will operate at de or several fixe d frequencies up to 10 kHz. Different and adapted modeling efforts have bee n undertaken both for the ergrodic area and the laminar zone. The basic tec hniques for the ergodic zone are held fine mapping and held line tracing; t he analysis provides the magnetic held structure in form of Poincare plots and the transport coefficients for the magnetic held lines. For the laminar zone a modeling is used which takes into account the typical aspects of th e scrape-off layer physics. A low frequency operation of the DED will distr ibute the heat flux over the relatively large area of the divertor target p late. The calculations show that the high frequency operation should impose a torque on the plasma edge which is of similar size as the one imposed by tangential NBI. (C) 1999 Elsevier Science B.V. All rights reserved.