Effect of magnetic configuration on real-time wall conditioning in DIII-D

Using EMC3-EIRENE modeling, the impact of parallel impurity forces on the edge transport of injected material and ionized impurities, including scrape-off layer (SOL) main ion flows, has been investigated. The study involved comparing impurity powder injections in different divertor configurations, namely DIII-D lower single null, upper single null, and double null configurations, with plasma edge transport and dust migration and ablation modeling. The injections, which were in powder and granular form, were conducted for real-time wall conditioning, ELM control, and divertor power exhaust at DIII-D [1]. Divertor configuration changes resulted in a redirection of SOL flows, which affected the conditioning of plasma-facing components on either the low field side or the high field side. Moreover, the injection location's poloidal shifts could modify the injected materials' penetration depths and trajectories in the plasma boundary. These changes had an impact on the local deposition of materials on plasma-facing components, which is essential for active conditioning and replenishment of functional coatings in future long-pulse scenarios.

[1] F. Effenberg et al 2022 Nucl. Fusion 62 106015 DOI 10.1088/1741-4326/ac899d