Modeling plasma-wall interactions in First Wall-Limiter geometry Original Research Article

We test the standard edge plasma code B2-solps5.0 on a model First-Wall Limiter (FWL) geometry. The presence of a tangency point between the solid wall and the magnetic separatrix introduces a singular point in the geometry. A quadrilateral computational mesh can fit the given configuration only if it is highly distorted, constituting a severe test for any numerical scheme. The original 5-point molecule adopted by B2-solps5.0 fails to solve the plasma transport equations near the singular point. A correction scheme is proposed, which is equivalent to adopting a 9-point stencil.