3D global impurity transport modeling with WallDYN and EMC3-Eirene

The global impurity migration code WallDYN was coupled to the 3D scrape off layer plasma solver EMC3-Eirene in order to make WallDYN applicable to 3D, non-toroidally symmetric, geometries. To make EMC3-Eirene suitable for migration studies its impurity transport module was extended to not just compute the impurity density in the plasma but also their deposition on the wall tiles. Originally EMC3 treats the impurity transport in the plasma as a diffusion convection problem thereby assuming immediate equilibration with the local background plasma in order to derive the local parallel convection velocity. While this is a reasonable approximation for light elements, it is not suitable for the treatment of heavy element which need significant time to equilibrate their velocity and temperature with the background plasma. Therefore EMC3-Eirene was augmented by a new kinetic impurity transport module that handles acceleration and thermalisation in a manner similar to what is implemented in the 2D trace impurity transport code DIVIMP. This paper will first describe the modification introduced in EMC3-Eirene and then show the differences between the impurity transport models and the new possibilities now available in WallDYN to interpret migration studies in non-toroidally symmetric geometries . PACS: 61.80.Jh, 52.25.Vy, 52.65, 52.40.Hf, EMC3, Erosion & deposition, Sputtering, Edge modeling