https://doi.org/10.1140/epjs/s11734-025-01564-5
Regular Article
Numerical study of fast ion loss and redistribution in the presence of energetic particle mode
1
School of Nuclear Science and Technology, University of Science and Technology of China, 230026, Hefei, China
2
College of Physics and Optoelectronic Engineering, Shenzhen University, 518060, Shenzhen, China
a
duansz@mail.ustc.edu.cn
b
hscai@mail.ustc.edu.cn
Received:
8
October
2024
Accepted:
4
March
2025
Published online:
13
March
2025
In this work, we have performed a general numerical investigation of the fast ion loss and redistribution in the presence of energetic particle mode (EPM) with different level of poloidal sideband, using the kinetic-MHD code M3D-K. It is found that the 
EPM, with the 
dominant poloidal harmonic and 
poloidal sideband, is excited by co-passing fast ions. The amplitude of sideband depends on the plasma density profile, which is linked to the continuum damping. By changing plasma density around the 
rational surface, the saturation amplitude of sideband decreases, while the saturation amplitude of harmonic remains almost unchanged. The loss and redistribution of fast ions are calculated with different plasma density profile, corresponding to different amplitude of sideband (called “strong sideband case” and “weak sideband case”). Compared to the weak sideband case, the resonant fast ions have a larger radial excursion in the strong sideband case, and thus, the loss and redistribution level is higher. These results indicate that, when the continuum damping linked to the equilibrium profiles is relatively small, a novel EPM with a considerable poloidal sideband could be excited and thus induces a more significant loss and redistribution of fast ions.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
