Abstract Details
Abstracts
Author: Yannis Kominis
Requested Type: Consider for Invited
Submitted: 2025-02-21 10:28:33
Co-authors: P.A. Zestanakis, Y. Antonenas, G. Anastassiou, M. Falessi
Contact Info:
National Technical University of Athens
9 Iroon Polytechniou, Zografou
Athens, 15772
Greece
Abstract Text:
The equilibrium magnetic field in fusion plasmas is modified by symmetry-breaking perturbations, arising either from intrinsically excited magnetohydrodynamic modes, or from externally applied fields. These modes interact strongly with particles through resonances, facilitating the transport of particles, energy, and momentum. In our previous works [1-4], we considered a Large Aspect Ratio (LAR) equilibrium and derived compact formulas for the Orbital Frequencies of the Guiding Center (GC) motion and the kinetic q-factor as a function of the particle's Constants Of Motion (COM), using a Hamiltonian Action-Angle formulation. The kinetic q-factor determines the selective conditions for resonant mode-particle interactions and allows for pinpointing the exact resonance locations in the COM and the GC phase space, whereas its local extrema correspond to the locations of Transport Barriers (TB) formed in the GC phase space [3,4].
In this talk, we review previous analytical results for LAR equilibria, and we present a computationally efficient semi-analytical geometrical method for Orbital Spectrum Analysis (OSA) of realistic numerically reconstructed equilibria. The calculated resonance diagrams contain all the essential information for the response of all particle species - including energetic particles – in the specific equilibrium under the presence of any type of multi-scale symmetry-breaking perturbations. Systematic comparisons with numerical particle tracing show an excellent agreement with the predicted locations of the resonances and the Transport Barriers.
[1] Y.Antonenas, G.Anastassiou and Y.Kominis, J. Plasma Phys. 87, 855870101 (2021)
[2] H.T.Moges, Y.Antonenas, G.Anastassiou, Ch.Skokos and Y.Kominis, Phys. Plasmas 31, 012302 (2024)
[3] G.Anastassiou, P.Zestanakis, Y.Antonenas, E.Viezzer and Y.Kominis, J. Plasma Phys. 90, 905900110 (2024)
[4] Y.Antonenas, G.Anastassiou and Y.Kominis, Phys. Plasmas 31, 102302 (2024)
Characterization: 4.0
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