Simulation of the plasma-wall interaction in a tokamak with theMonte Carlo code ERO-TEXTOR

The interaction of plasma with the walls has been one of the criticalissues in the development of fusion energy research. On the one hand,plasma induced erosion can seriously limit the lifetime of the wallcomponents, while, on the other hand, eroded particles can be transported intothe core plasma where they lead to dilution of the fusion plasma andto energy losses due to radiation. Low-Z wall materials induce only small radiationlosses in the plasma core but suffer from large physical sputtering rates. Carbonbased materials in addition suffer from chemically induced erosion.High-Z wall materials show significantly smallererosion but lead to large radiation losses. One of the main goals ofpresent plasma-wall studies is to find a special choice of wallmaterials for steady state plasma scenarios that will provide anoptimum with respect to fuel dilution, radiation losses, wall lifetimeand fuel inventory in the walls. To obtain a better understanding of theprocesses and to estimate the plasma-wall interactionbehaviour in future fusion devices the 3-D Monte Carlo codeERO-TEXTOR, based originally on the ERO code, has beendeveloped. It models the plasma-wall interaction and transportprocesses in the vicinity of a surface positioned in the boundarylayer of TEXTOR. The main aim is to simulate the erosion andredeposition behaviour of different wall materials under variousplasma conditions and to compare this with experimental results. Thiscontribution describes the main features of the ERO-TEXTOR code andgives some examples of simulation calculations to illustrate theapplication of the code.