Deposition probe investigations of the sol of T-10

Abstract

Several hundred systematic deposition probe measurements were carried out in the SOL of T-10 to investigate the time development of the Fe-impurity flux at various radial positions. During these investigations the discharge conditions as well as the limiter configuration were varied over a wide range. Some qualitative guiding principles are given for deposition probe measurements and their interpretation. On the basis of the radial dependence of the iron flux during both the plateau and the end phase of the tokamak discharge, the influence of erosion processes as well as of local sources and enhanced transport on the iron deposition is discussed. The experiments show an immediate relation between the direction of the toroidal magnetic field and the evolution of the impurity flux during the plateau phase, no influence of various limiter arrangements could be detected.