Near field divertor structure of the helical perturbation current produced by the dynamic ergodic divertor

The proposed dynamic ergodic divertor experiment on TEXTOR has inspired the analysis of the near field of the perturbation current. For simplicity, the analysis is performed in cylindrical geometry. In the near field of a resonant perturbation current the field lines are diverted such that a helical divertor is formed. The required perturbation amplitude is about an order of magnitude smaller than the one required for the poloidal divertor. At this rather low perturbation current, the particle diversion efficiency is lower than that of a poloidal divertor, amounts to more than 50% and is quite considerable.