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| Hauptverfasser: | , , , , |
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| Format: | Preprint |
| Veröffentlicht: |
2025
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| Schlagworte: | |
| Online-Zugang: | https://arxiv.org/abs/2503.15278 |
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| _version_ | 1866916657791762432 |
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| author | Albert, Christopher G. Grassler, Georg S. Kasilov, Sergei V. Markl, Markus Schatzlmayr, Jonatan |
| author_facet | Albert, Christopher G. Grassler, Georg S. Kasilov, Sergei V. Markl, Markus Schatzlmayr, Jonatan |
| contents | Symplectic integrators with long-term preservation of integrals of motion are introduced for the guiding-center model of plasma particles in toroidal magnetic fields of general topology. An efficient transformation to canonical coordinates from cylindrical and flux-like coordinates is discussed and applied using one component of the magnetic vector potential as a spatial coordinate. This choice is efficient in both, theoretical and numerical developments and marks a generalization of magnetic flux coordinates. The transformation enables the application of conventional symplectic integration schemes formulated in canonical coordinates, as well as variational integrators on the guiding-center system, without requiring magnetic flux coordinates. Symplectic properties and superior efficiency of the implicit midpoint scheme compared to conventional non-symplectic methods are demonstrated on perturbed tokamak fields with magnetic islands and stochastic regions. The presented results mark a crucial step towards gyrokinetic models that conserve physical invariants. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_15278 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Symplectic integration of guiding-center equations in canonical coordinates for general toroidal fields Albert, Christopher G. Grassler, Georg S. Kasilov, Sergei V. Markl, Markus Schatzlmayr, Jonatan Plasma Physics Computational Physics Symplectic integrators with long-term preservation of integrals of motion are introduced for the guiding-center model of plasma particles in toroidal magnetic fields of general topology. An efficient transformation to canonical coordinates from cylindrical and flux-like coordinates is discussed and applied using one component of the magnetic vector potential as a spatial coordinate. This choice is efficient in both, theoretical and numerical developments and marks a generalization of magnetic flux coordinates. The transformation enables the application of conventional symplectic integration schemes formulated in canonical coordinates, as well as variational integrators on the guiding-center system, without requiring magnetic flux coordinates. Symplectic properties and superior efficiency of the implicit midpoint scheme compared to conventional non-symplectic methods are demonstrated on perturbed tokamak fields with magnetic islands and stochastic regions. The presented results mark a crucial step towards gyrokinetic models that conserve physical invariants. |
| title | Symplectic integration of guiding-center equations in canonical coordinates for general toroidal fields |
| topic | Plasma Physics Computational Physics |
| url | https://arxiv.org/abs/2503.15278 |