A CFD onion-skin model for the interpretation of edge experiments

Earlier onion-skin modelling, O-SM, of divertor edge plasmas, which uses experimental target measurements of I-sat and T-e as boundary conditions, has shown good agreement with standard 2-D code solutions, except for detached plasma conditions. The inability to produce stable, detached solutions motivated the development of an improved O-SM solver using standard CFD techniques, which overcame earlier stability problems. A smooth transition between attached and detached regimes has been observed by reducing target T-e with fixed I-sat. In the case of strong detachment, typically with T-e below 1 eV, it is found that upstream quantities are highly sensitive on the input target conditions. The solutions show the characteristic detachment profiles both along and across the magnetic field. (C) 1999 Elsevier Science B.V. All rights reserved.