2025 – Investigation of remobilized dust transport in the divertor using the impurity powder dropper

Investigation of remobilized dust transport in the divertor using the impurity powder dropper

2025 Research Campaign, Plasma-Material Interactions

Purpose of Experiment

This experiment aims to determine if strike point sweeps are effective at removing divertor slag by utilizing the impurity powder dropper to simulate slag deposition. Distributions of dust and powder layers in the machine will be determined primarily by an in-vessel dust collection and LIBS analysis. Boron will be the primary impurity injected by the dropper, as this material is of critical importance to metal machines such as ITER that will need to boronize to reach high performance scenarios. DiMES will be used to characterize the initial layers of boron powder and the effectiveness of the sweeps at removing these layers. In-situ diagnostics such as divertor impurity spectroscopy and camera techniques will measure boron erosion and capture dust transport.

Experimental Approach

The experimental approach is to first create thick boron films on the divertor that will be swept over, followed by the creation of SiC films to represent an initial distribution. Materials characterization analysis of the collected dust will determine distributions after sweeping and the elemental composition. These results will then be used to benchmark a yet-to-be developed slag modeling code that can inform future slag removal scenarios. The buildup of slag is a critical issue for future machines with solid walls that can threaten reactor operation. Removing slag safely from these devices is necessary for their long term viability, and this experiment will determine if strike point sweeping is a potential solution.