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

Abstract

The interaction of plasma with the walls has been one of the critical issues in the development of fusion energy research. On the one hand, plasma induced erosion can seriously limit the lifetime of the wall components, while, on the other hand, eroded particles can be transported into the core plasma where they lead to dilution of the fusion plasma and to energy losses due to radiation. Low-Z wall materials induce only small radiation losses in the plasma core but suffer from large physical sputtering rates. Carbon based materials in addition suffer from chemically induced erosion. High-Z wall materials show significantly smaller erosion but lead to large radiation losses. One of the main goals of present plasma-wall studies is to find a special choice of wall materials for steady state plasma scenarios that will provide an optimum with respect to fuel dilution, radiation losses, wall lifetime and fuel inventory in the walls. To obtain a better understanding of the processes and to estimate the plasma-wall interaction behaviour in future fusion devices the 3-D Monte Carlo code ERO-TEXTOR, based originally on the ERO code, has been developed. It models the plasmawall interaction and transport processes in the vicinity of a surface positioned in the boundary layer of TEXTOR. The main aim is to simulate the erosion and redeposition behaviour of different wall materials under various plasma conditions and to compare this with experimental results. This contribution describes the main features of the ERO-TEXTOR code and gives some examples of simulation calculations to illustrate the application of the code.

Effect of E×B driven transport on the deposition of carbon in the outer divertor of ASDEX Upgrade

“…The detailed 3D trajectories of the injected impurities were then calculated with the ERO code [5], using the SOLPS solutions for T e , T i , n e , v and electric potential V p to describe the plasma background [2]. ERO calculates the formation of the carbon layer, including re-erosion and re-deposition, which is compared to the NRA measurements.…”

“…Therefore, the present modelling assumes S(CH,CH + )=1 and S=0 for other hydrocarbons, which tends to broaden the patterns compared to a species-independent S eff . For carbon, sticking probabilities are calculated according to TRIM [5].…”

Modelling of carbon deposition from CD4injection in the far scrape-off layer of TEXTOR

“…This measurement revealed a linear increase of deposition with the amount of injected CD 4 and thus shows that the deposition is determined by CD 4 injection, whereas background carbon deposition can be neglected. Figure 3 summarizes the measured deposition efficiencies on the QMB (i.e.…”

“…injected CD 4 (variation between 1.23 × 10 19 and 3.32 × 10 20 molecules per discharge) with a fixed radial position of the cylinder at 52 cm. This measurement revealed a linear increase of deposition with the amount of injected CD 4 and thus shows that the deposition is determined by CD 4 injection, whereas background carbon deposition can be neglected.…”

1D Modeling of LHD Divertor Plasma and Hydrogen Recycling

“…The model presented here is intended to be employed in our future simulation studies as a model of divertor legs to connect the following two simulation codes; EMC3 code [2] for the ergodic layer and ERO code [3] for the plasma-surface interactions at the divertor. The former code solves fluid equations to obtain equilibrium plasma profiles in the stochastic magnetic field and the latter solves impurity's equations author's e-mail: kawamura.gakushi@nifs.ac.jp of motion to obtain the sputtering yield, time evolution of surface conditions and impurity transport near a target plate.…”