Erosion–deposition mapping of the toroidal pump limiter of Tore Supra

Abstract Analyses of erosion and deposition over the toroidal pump limiter of Tore Supra were performed combining scanning electron microscopy, confocal microscopy and lock-in thermography. The consistency between the different methods allows a complete mapping of the eroded and deposited mass of carbon to be performed. ∼920 g of eroded carbon and ∼520 g of deposited carbon are found, showing that more than half of the eroded carbon is redeposited on the limiter. The highest deposition zones are close to the eroded zones. The gap deposition contribution is estimated at ∼23%, mostly from the erosion zones and with a main contribution from the low field side of the tile toroidal gap surfaces. Raman microscopy and transmission electron microscopy in-depth analyses show that the structure of deposits is non-homogeneous, in agreement with a deuterium impoverishment of the deep layers.