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Title: A penalization technique to model plasma facing components in a tokamak with temperature variations

To properly address turbulent transport in the edge plasma region of a tokamak, it is mandatory to describe the particle and heat outflow on wall components, using an accurate representation of the wall geometry. This is challenging for many plasma transport codes, which use a structured mesh with one coordinate aligned with magnetic surfaces. We propose here a penalization technique that allows modeling of particle and heat transport using such structured mesh, while also accounting for geometrically complex plasma-facing components. Solid obstacles are considered as particle and momentum sinks whereas ionic and electronic temperature gradients are imposed on both sides of the obstacles along the magnetic field direction using delta functions (Dirac). Solutions exhibit plasma velocities (M=1) and temperatures fluxes at the plasma–wall boundaries that match with boundary conditions usually implemented in fluid codes. Grid convergence and error estimates are found to be in agreement with theoretical results obtained for neutral fluid conservation equations. The capability of the penalization technique is illustrated by introducing the non-collisional plasma region expected by the kinetic theory in the immediate vicinity of the interface, that is impossible when considering fluid boundary conditions. Axisymmetric numerical simulations show the efficiency of the method to investigate themore » large-scale transport at the plasma edge including the separatrix and in realistic complex geometries while keeping a simple structured grid.« less
Authors:
; ; ;  [1] ;  [1] ; ;  [2]
  1. Aix Marseille Universite, CNRS, Centrale Marseille, M2P2 UMR 7340, 13451 Marseille (France)
  2. CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)
Publication Date:
OSTI Identifier:
22382116
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Computational Physics; Journal Volume: 274; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AXIAL SYMMETRY; BOUNDARY CONDITIONS; COLLISIONAL PLASMA; COMPUTERIZED SIMULATION; DELTA FUNCTION; FIRST WALL; HEAT TRANSFER; MAGNETIC FIELDS; MATHEMATICAL SOLUTIONS; PLASMA FLUID EQUATIONS; PLASMA SCRAPE-OFF LAYER; PLASMA SIMULATION; TEMPERATURE GRADIENTS; TOKAMAK DEVICES