Quantifying toroidal asymmetries on divertor metal targets, fuel retention, and synergistic effects of B and SiC powders injection

2025 Research Campaign, Plasma-Material Interactions

Purpose of Experiment

This experiment aims to understand and quantify the toroidal asymmetries in boron (B) deposition on plasma-facing components (PFCs) in DIII-D using real-time powder injection. The study will assess the distribution of boron coatings on plasma-facing components and how the magnetic field configuration influences them. Specifically, the interaction of B with small-scale tungsten targets will be studied, which is relevant for deploying boronization in ITER. The experiment will also explore the synergistic effects of siliconization through SiC powder injection, investigating if it can further improve wall conditions through oxygen gettering. The results will inform real-time wall conditioning and coating strategies in fusion reactors to reduce recycling and mitigate high-Z impurity influxes for high-performance long-pulse operation.

Experimental Approach

The experiment involves a series of controlled scans of the toroidal magnetic field (Btor) to manipulate the magnetic flux tube connections from the impurity powder dropper (IPD) to the divertor. These scans will help identify the extent of boron deposition asymmetry on tungsten DiMES targets. In-situ measurements of boron and high-Z impurity fluxes and post-mortem analysis of the deposition on metal targets, including Laser Induced Breakdown Spectroscopy (LIBS), will provide comprehensive data on the deposition patterns. SiC powder injection will also be tested to evaluate its impact on wall conditioning. The results from this experiment will be crucial for validating 3D fluid models such as EMC3-EIRENE and will support the development of real-time wall conditioning techniques in ITER and other next-step devices.

See more details, including project leads, at U.S. Department of Energy, Office of Scientific and Technical Information (OSTI).