Plasma Physics Seminar
Friday, April 19
2241 Chamberlin Hall
Speaker: Dr. Oliver Schmitz, Institute for Energy and Climate Research of the Research Center Jülich, Germany
"Three-Dimensional Edge Transport and the Impact on Plasma Surface Interactions with Resonant Magnetic Perturbation Fields at Tokamaks"
Abstract: Three-dimensional (3D) magnetic perturbation fields are applied to high temperature plasma experiments to optimize the transport in the plasma edge and the resulting plasma wall interaction. While 3D magnetic field topologies are inherent to stellarator devices, the application of small, external 3D magnetic perturbation fields is a new and promising approach in tokamaks to control cyclic edge instabilities causing impulsive heat and particle loads to the first wall. The external 3D field applied breaks the axisymmetry and the standard assumptions for plasma edge transport have to be reconsidered. Thus the resulting plasma surface interaction is governed by the 3D field structure. This talk will survey experimental results on the formation of such a 3D plasma boundary and the stationary plasma edge transport is studied with a Monte-Carlo fluid plasma and kinetic neutral transport model (EMC3-Eirene) in direct comparison to the experiment at TEXTOR and DIII-D. It is shown that a 3D plasma boundary is induced resulting in 3D plasma surface particle and heat fluxes. Experimental quantification of the resulting material erosion at the wall elements shows that the net-erosion characteristic in a 3D boundary is highly dependent on the actual location in the 3D topology. The consequences of these experimental observations for RMP ELM control at ITER are addressed using EMC3-Eirene modeling.