A new scientific paper has been published by the UNITUS Nuclear Fusion Research team, concerning inter-machine plasma perturbation studies in EU-DEMO relevant scenarios.

The DEMO wall protection strategy is among one of the key issues to be solved to achieve commercial nuclear fusion reactors and fusion energy. Therefore, the development of comprehensive analyses is mandatory to assess how transient perturbations on plasma shape control and on vertical stability affect the tokamak performances with elongated plasmas. Moreover, the design of the limiter structures needs a deep understanding also of the effects induced by one of the most severe load conditions to occur in tokamaks, the Vertical Displacement Events (VDEs). Electromagnetic loads during VDEs are among the DEMO limiter’s design drivers because they provide specifications regarding their electromagnetic and mechanical performances. Therefore, predictive simulations of the final plasma position and of EM loads following a VDE are essential to understand the operational space of the future commercial nuclear fusion reactors. For this purpose, a multi-tokamak study has been carried out and an inter-machine database has been built and populated with experimental transient plasma perturbations and VDEs from JET and ASDEX Upgrade (AUG) tokamaks. Thanks to statistical analyses carried out on the data collected into the database, some transient plasma perturbations (namely, low-to-high confinement mode transitions, high-to-low confinement mode transitions and Edge Localized Modes) have been characterized. They have been chosen since they may lead to high control actions by the vertical stability system in terms of variations of the plasma’s internal parameters and vertical displacements. Then, experimental transient plasma perturbations have been properly scaled to DEMO reference geometries with different magnetic configurations. Finally, initial predictive electromagnetic loads on DEMO limiter structures are calculated in the case of VDEs following plasma perturbations, providing lessons to be learnt in view of DEMO.