2024/12/27 by Kaiyu Zhang, W. Zholobenko, Zhang, Kaiyu +7
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Magnetic confinement fusion research #Plasma Physics (physics.plasm-ph) #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2412.19390
openalex publication_date 2024/12/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Plasma turbulence in the edge of magnetic confinement devices is customarily treated as full-f due to large fluctuations. For computational efficiency, field-aligned coordinates are employed, separating the magnetic field into equilibrium B0 and delta-f perturbations which are handled by the magnetic flutter operators. Evolving the full-f pressure with delta-f magnetic perturbations can cause inconsistency since the latter contain background components such as the Shafranov shift, which are actually parts of the equilibrium magnetic field. Such background components (Bs) contained in the magnetic perturbations undermine the field-aligned numerics when treated as flutter: errors arise if Bs/B0≪ l_⊥/h_∥ is not satisfied, with the perpendicular turbulence scale l_⊥ and the parallel grid distance h_∥. We find that the commonly used removal of Bs by subtracting the toroidal average of magnetic perturbations intervenes in the Alfvén dynamics, causing spurious E× B transport. Instead, we propose an improved method to dynamically filter out the evolving background from the turbulent magnetic fluctuations in the time domain. The filter is verified in both low and high confinement tokamak conditions, confirming its capability to preserve the turbulence fidelity, provided sufficient filter width.