Localized impurity flux measurements on Wendelstein 7-AS

Our measurements concentrate on one of the bulk boronized limiters and the poloidal plane intersecting this limiter. Impurity influxes as a function of time are obtained for fix viewing directions, while spatial distributions are obtained by scanning the mirror during the discharge or by shot-to-shot variations of the line of sight, see fig. 1. All ion species within one spectrum (typically of 15 to 30 nm spectral range) are monitored simultaneously. In the following we first concentrate on a comparison of influxes of carbon and boron from the limiter. In a next step, the poloidal distribution of BI-BIV, CII-CV and OII-OV atoms and ions is investigated. Finally, the localizations and radial extensions of the above mentioned ions are investigated in more detail and the dependence of the radial position and width of these radial emissivity profiles on plasma parameters is presented. (orig.)