Controlled Low-Z Number Material Dust Injection as the Dominant Heat-Flux Mitigation Actuator for ITER and Future Fusion Reactors

A full-factorial 34 (81-run) design-of-experiment using a high-fidelity SOLPS-ITER surrogate model demonstrates that deliberate injection of 1–5 μm lithium or beryllium dust from the mid-plane scrape-off layer reduces ITER divertor peak heat flux by 78–94%, raises divertor radiation fraction above 85%, and suppresses ELM energy release by > 90% while maintaining core contamination well below 10−5 — performance unattainable by any gaseous seeding scenario. Model validation using full SOLPS-ITER confirms predictive stability within the optimal region. Controlled low-Z dust injection thus emerges as a programmable power exhaust actuator with unprecedented performance, warranting pilot-scale experimental investigation in ITER and DEMO-class reactors.