Göttingen 2025 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 17: Poster Session II
P 17.29: Poster
Mittwoch, 2. April 2025, 16:15–18:15, ZHG Foyer 1. OG
The avalanche source for a 3D particle in cell model of runaway electrons — •Fiona Wouters1, Matthias Hoelzl1, Hannes Bergstroem1, Guido Huijsmans2,3, and Jan van Dijk2 — 1Max Planck Institute for Plasma Physics, Boltzmannstraße 2, 85748 Garching, Germany — 2Eindhoven University of Technology, Groene Loper 3, 5612 AE Eindhoven, the Netherlands — 3CEA, IRFM, 13115 Saint-Paul-lez-Durance, France
Disruptions, i.e. major instabilities in which plasma confinement is lost, are a significant threat to tokamak operation. During a disruption the resistivity of the plasma increases as the thermal energy is quickly lost, causing the current to decrease. Due to the self-inductance of the plasma this leads to the generation of a strong parallel electric field. As the friction force experienced by fast electrons in a plasma has the peculiarity that it decreases with increasing electron velocity, this electric field can accelerate some fast electrons to relativistic velocities. These so-called runaway electrons (REs) can then exponentially multiply due to large-angle collisions with thermal electrons in what is known as the runaway avalanche. Because the avalanche is exponentially sensitive to the pre-disruption plasma current, this can lead to multi-MA RE beams in large future devices such as ITER, which may cause severe localized wall damage. Simulations including the RE sources in realistic 3D fields are needed to further the understanding of RE generation and losses and develop viable mitigation scenarios. For this purpose the avalanche source was implemented in the 3D nonlinear extended MHD code JOREK.
Keywords: Runaway electrons; Runaway avalanche; Disruptions; Particle in Cell; Collisions