Contrib. Plasma Phys. 44, No. 1-3, 25 – 30 (2004) / DOI 10.1002/ctpp.200410003 Implementation of the EMC3-EIRENE code on TEXTOR-DED: accuracy and convergence study M. Kobayash ∗1 , Y. Feng 2 , F. Sardei 2 , D. Reiter 1 , D. Reiser 1 , and K. H. Finken 1 1 Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, Euratom Association, Trilateral Euregio Clus- ter, 52425 Juelich, Germany 2 Max-Planck-Institut fuer Plasmaphysik, Euratom Association, D-17491 Greifswald, Germany Received 5 September 2003, accepted 9 Februar 2004 Published online 23 April 2004 Key words Tokamak, 3D modelling, plasma transport. PACS 52.55.Fa, 52.65.Pp c  2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 Introduction Recently a three dimensional modelling of edge plasma transport in the TEXTOR-DED configuration has been carried out [1], using the 3D edge transport code, EMC3-EIRENE [2][3]. EMC3 solves the time-independent Braginskii’s fluid equations for particle, momentum and energy [4], by a Monte Carlo scheme in almost any arbitrary 3D geometry. At the application of EMC3-EIRENE to TEXTOR-DED, the code was tested in various aspects in order to find the feasible range of the application. In this paper, the results of the tests are reported and the validity of the 3D modelling with EMC3-EIRENE is discussed. 2 Mathematical basis The application of the Monte Carlo scheme to solving plasma fluid equations is explained with the relation between a jump process and a diffusion equation. For simplicity, consider an one dimensional problem, and let f (x, t) the distribution function (the probability density function) of the quantity of interest. The jump process from the point (x − ∆x, t) to (x, t +∆t) can be expressed as, f (x, t +∆t)=  d(∆x)p(x − ∆x, ∆x)f (x − ∆x, t), (1) where p(x, ∆x) is the probability density (transition probability) of the jump with step size ∆x in time ∆t starting from x. Expanding the equation with respect to x we get, f (x, t +∆t)= f (x, t) − ∂ ∂x (∆x p f (x, t)) + 1 2 ∂ 2 ∂x 2 (∆x∆x p f (x, t)) + O(∆t 2 ), (2) here, ∆x p ≡  d(∆x)∆xp(x, ∆x), (3) ∆x∆x p ≡  d(∆x)d(∆x)∆x∆xp(x, ∆x; x, ∆x) . (4) ∗ Corresponding author: e-mail: masahiro@nifs.ac.jp, Phone: +81 572 58 2268, Fax: +81 572 58 2630 c  2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim