ASDEX Upgrade Letter No. 26: In Garching for Europe – Fusion Research with the ASDEX Upgrade Tokamak

ASDEX Upgrade Letter | No 26 | July 2025 IN GARCHING FOR EUROPE – FUSION RESEARCH WITH THE ASDEX UPGRADE TOKAMAK Max Planck Institute for Plasma Physics Fish-eye view into the interior of the ASDEX Upgrade vacuum vessel in August 2024, following the installation of the new upper divertor (photo: V. Rohde). Editorial After a two-year maintenance period, ASDEX Upgrade resumed operations in November 2024. This upgrade phase introduced significant changes to enhance operational flexibility, particularly in divertor configurations and exhaust handling. A key enhancement was the installation of a new upper divertor, enabling alternative magnetic configurations and improved plasma exhaust management. Since August 2022, ASDEX Upgrade has undergone maintenance to install components like a helium-extracting cryopump, inner and outer divertor modules, and two concentric coils capable of producing a variety of alternative divertor geometries. A newly designed flat divertor was also added for bi-directional magnetic helicity, supporting novel operational regimes. The reassembly of ASDEX Upgrade was completed on time in autumn 2024, and the electrical connection of the new coils has become operational in spring 2025. With the coils' activation, the studies of alternative divertor configurations is starting now, an overview of which is given in this special edition. We also describe the upper divertor components, and outline their installation strategy. Irene Zammuto, Head of the AUSBAU Group (Photo: MPI for Plasma Physics)