The alternative divertor configuration (ADC) programme of EUROfusion has reached a significant milestone, gaining strong visibility through multiple publications in high-impact scientific journals and the introduction of innovative solutions across several leading tokamaks.
Fusion reactors operate at extremely high power levels in the divertor region, where heat and particle fluxes are most intense. The ADC programme was launched to tackle this issue by exploring new divertor configurations that could help minimizing the heat loads and gaining crucial insights into the relevant dominant physics processes leading to a divertor operating regime called detachment.
Breakthrough Results Across European Tokamaks include:
- TCV Tokamak:
- A new ADC, the X-Point Target Radiator (XPTR), was introduced and implemented by Kenneth Lee and coworkers, as reported in Physical Review Letters [1]. XPTR creates an intense radiation front near a secondary X-point close to the divertor targets, enabling access to detached plasma states and reducing heat fluxes by up to 80%.
- MAST Upgrade:
- In a Communications Physics article, Kevin Verhaegh and his team summarized years of ADC research, demonstrating that even moderate divertor shaping can dramatically reduce target heat loads and expand the operational regime for plasma detachment [2].
- Bob Kool and colleagues showed that reduced detachment sensitivity in the Super-X divertor—a flagship ADC of MAST Upgrade—enables improved real-time power exhaust control [3].
- ASDEX Upgrade (AUG):
- The year 2025 marked the start of ADC studies on AUG, following a major upgrade that allows for various magnetic configurations, including snowflake (SF), compact radiative divertor (CRD), and X-divertor (XD) setups.
- These configurations have been successfully developed at power levels up to and beyond 20 MW in both L- and H-mode.
- Early analysis indicates that, at equivalent heating power, the SF configuration achieves an easier access to plasma detachment compared to the traditional single-null setup.
Read the full publications about these results here:
- [1] K. Lee et al., X-Point Target Radiator Regime in Tokamak Divertor Plasmas, Phys. Rev. Lett 134 (2025) 185102; https://doi.org/10.1103/PhysRevLett.134.185102
- [2] K. Verhaegh et al., Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge, Comm. Phys. 8 (2025) 215, https://doi.org/10.1038/s42005-025-02121-1
- [3] B. Kool et al., First demonstration of Super-X divertor exhaust control for transient heat load management in compact fusion reactors, Nature Energy, https://doi.org/10.21203/rs.3.rs-5059325/v1