Erlangen 2026 – scientific programme

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P: Fachverband Plasmaphysik

P 16: Poster Session Plasma Physics

P 16.7: Poster

Thursday, March 19, 2026, 13:45–15:45, Redoutensaal

Integrated modelling of sawtooth cycles in tokamak plasmas — •Federico Stefanelli, Emiliano Fable, Clemente Angioni, Michael Bergmann, Davide Brioschi, Anja Gude, Philipp Lauber, Oleg Samoylov, Riccardo Stucchi, Markus Weiland, Haowei Zhang, and Hartmut Zohm — Max Planck Institute for Plasma Physics, Garching

Sawtooth cycles are periodic relaxations of the plasma core commonly observed in tokamak discharges. The cycle is characterized by a rapid MHD-driven collapse of the core temperature, density and current profiles, followed by a profile recovery driven by continued heating. Sawtooth cycles limit core pressure and thus lower the plasma performance. Even more critically, they can trigger secondary MHD instabilities, which in turn can lead to disruptions. On the other hand, the crash expels impurities from the core, aiding in the control of impurity and, in a reactor, helium ash accumulation. For these reasons, accurate modelling is essential for predictive transport simulations and reliable control of plasma behavior in future devices. An integrated model of these cycles is presented, which includes also the effects of additional MHD activity. The phases of a sawtooth cycle: (1) onset criterion, (2) collapse and (3) the recovery phase are modelled either via first-principles (1) and (3) or with an ad-hoc relaxation model (2). The collapse of the fast particle population and rotation profiles are also considered, as they actively and passively affect the sawtooth cycle and are in turn affected by it. The results are validated on ASDEX Upgrade discharges in presence of NBI and ECRH heating schemes.

Keywords: Sawtooth Cycles; Integrated Modelling