Optimising stellarator divertor plates in the flexible magnetic configurations of HSX

The commercial viability of stellarator reactors requires an acceptable exhaust solution i.e. to efficiently remove Helium ash from the plasma whilst avoiding excessive heat loads on the plasma-facing components (PFCs). However, both the optimal edge magnetic structure and shape of solid targets needed to achieve this are open questions. The optimised stellarator HSX (Helically Symmetric eXperiment), located at the University of Wisconsin-Madison, is ideally suited to exploring these questions by virtue of its flexible edge magnetic configuration and its planned divertor upgrade. In this work, we simulate the heat deposition on candidate HSX divertor plates using a range of magnetic topologies. For this we use the EMC-Lite code [1], which uses a reduced physical model to quickly predict the heat loads on PFCs. We also present a divertor plate optimisation algorithm which uses EMC3-Lite in order to minimise divertor heat loads. The performance and resiliency of these plates to changes in magnetic configuration is shown.



[1] Feng, Y., et al. Plasma Physics and Controlled Fusion 64.12 (2022): 125012.