Impurity flux onto the divertor plates of ASDEX

Fluxes of metallic impurities onto the divertor plates of ASDEX with different plasma parameters were collected and resolved in space and time by means of five carbon strips wound parallel on a cylindrical core rotating during the discharge. Ion beam accelerator analysis (Rutherford Backscattering Spectroscopy (RBS) , Proton Induced X-Ray Emission (PIXE)) of five carbon strips exposed to the plasma show a different distribution of the Fe and Cu atoms across the scrape-off layer (SOL). The Fe fluxes collected in the centre of the SOL are related to the Fe content in the central plasma; the Cu deposition has a maximum value close to the Cu divertor plates, indicating evaporation or sputtering from the plates. (orig.)