Fluid modeling of an ELMing H-mode and a RMP H-mode

In this paper, we investigate the role of wall conditions during the density pump-out observed in Resonant Magnetic Perturbation (RMP) experiments. We use a 2D fluid code, coupled to a neutral Monte-Carlo code (SOLPS5) to model a reference ELMing H-mode. Next we modify either the recycling at the target plates or the pumping efficiency at the pump entrance. This causes a change in upstream profiles, that alone cannot account for the shape change observed in the RMP H-mode. Therefore, the radial transport must be altered to match the RMP H-mode. By comparing the transport model for the ELMing H-mode and the RMP H-mode, we show that inside the separatrix an increase in transport is necessary to model the effects of the applied perturbed field in RMP H-mode. (C) 2009 Elsevier B.V. All rights reserved