Carbon and neon penetration near a neutraliser plate of the Tore Supra ergodic divertor

Abstract The ergodic divertor (ED) of Tore Supra has been shown to diminish core impurity contamination. To assess this effect on injected neon a scan in ED perturbation intensity is reported. Spectroscopic observations of neon on an ED neutraliser plate (NP) show that the penetration of low neon ionisation stages increases with the perturbation intensity while the ratio of the edge to central neon density increases. A scan in volume average density is also reported, showing that, at maximum ED perturbation, the carbon penetration decreases with increasing densities up to values close to detachment. Modelling of these experiments with the 2D code IMPEN and the 3D code BBQ shows the importance of a realistic description of the neutral source and of n e and T e in the vicinity of the NP.