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arXiv · 2610.31367

Synthetic 2D magnetic turbulence with controlled island structuring

Yari De Paep·Daniela Maci·Rony Keppens
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Abstract

Magnetic turbulence remains up to this day not fully understood, despite its important role in the behavior of plasmas. A recurring ingredient in plasma turbulence is the spontaneous formation and evolution of plasmoids. These represent magnetic islands on current sheets in two-dimensional turbulent magnetic fields that are consistently found in high-resolution direct numerical simulations (DNSs) using a magnetohydrodynamic description. However, such simulations require considerable amounts of computational power. Synthetic turbulence models provide an alternative, cheap approach to the generation of fully-developed turbulent fields. In this work, we first present an extension of our open-source, general synthetic turbulence BxC toolkit that is specifically tailored to generate 2D turbulent magnetic fields. We then use a novel physically motivated, but purely geometric construction that generates current sheet island chains, which results in fields that visually match the ones obtained through DNSs. We show how this construction affects the magnetic field lines and find a correlation with the formation of magnetic O-points and X-points. The magnetic flux and size of the islands in the field are found to match well with theoretical scaling laws. Lastly, we show BxC's capabilities by generating a 2D $N\times N$ turbulent magnetic field of resolution $N = 100000$, going beyond the state-of-the-art reached by simulations, on a single CPU with modest computational resources. Our construction maintains direct control over the inertial range, and allows to make morphological changes to the plasmoids and fields, demonstrating plasmoid appearance, disappearance and merging.

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Yari De Paep, Daniela Maci, Rony Keppens. 2026-10-22. Synthetic 2D magnetic turbulence with controlled island structuring. https://arxiv.org/abs/2610.31367

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