Erosion yields of carbon under various plasma conditions in Pilot-PSI

TL;DR

This study investigates how different plasma conditions affect carbon erosion yields on graphite targets in a fusion-relevant environment, revealing the influence of ion energy, surface morphology, and insulating coatings.

Contribution

It provides new insights into the effects of plasma parameters and target geometry on carbon erosion in fusion devices, using optical spectroscopy and mass loss measurements.

Findings

Gross chemical erosion varies with plasma exposure and surface morphology.

Net erosion yield increases with boron-nitride insulation coverage.

Erosion behavior depends on ion impact energy and target geometry.

Abstract

Fine-grain graphite targets have been exposed to ITER divertor relevant plasmas in Pilot-PSI to address material migration issues in fusion devices. Optical emission spectroscopy and mass loss measurements have been employed to quantify gross chemical erosion and net erosion yields, respectively. Effects of the ion impact energy and target geometry on carbon erosion yields have been studied. It is concluded that temporal evolution of gross chemical erosion is strongly connected with changes in morphology of plasma exposed surfaces. The net carbon erosion yield is increased when the targets are partly covered by insulating boron-nitride rings.