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arXiv · 2609.25480

Current Sheet Fragmentation in the Course of Repeated Eruptive Magnetic Flux Emergence

Vaggelis Karantanis·Loukas Vlahos·Heinz Isliker·Angelos Giannis·Vasilis Archontis
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Abstract

Magnetic reconnection between emerging magnetic flux and the ambient coronal field fundamentally drives solar jets. We use three-dimensional resistive-MHD simulations of eruptive flux emergence to investigate how the large-scale current sheet formed at the interface fragments during recurrent jet activity. The simulations show that jet formation and current-sheet disruption are coupled elements of a single multiscale process. The current structures developing along open field lines and within the jet are relatively weak, exhibiting a predominantly filamentary morphology. In contrast, the larger structures linked to the closed-field topology are noticeably stronger, and the eruptive development of the emerging flux further increases both their number and strength. The parallel-current distributions within the closed magnetic field lines region exhibit Gaussian central cores with pronounced non-Gaussian tails, implying a small subset of strong, intermittent structures. Magnetic spectra follow a power law with a Kolmogorov-like slope in the large-scale range, becoming much steeper in the small-scale range---consistent with reconnection-mediated magnetic structuring. Box-counting analysis shows that the strongest current structures have a fractal dimension $D_{\mathrm{f}} \simeq 2$, indicating a fragmented population of sheet-like coherent structures. Cluster analysis further reveals broad, power-law distributions of cluster volumes and their Ohmic dissipation energies, with individual events reaching $\sim 10^{20}$--$10^{25}$ erg over their estimated lifetimes. These results demonstrate that eruptive flux emergence can self-consistently transform a global reconnecting current sheet into a localized, intermittent, sheet-dominated dissipative network, providing a natural environment for impulsive coronal heating and motivating future particle-acceleration studies.

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Vaggelis Karantanis, Loukas Vlahos, Heinz Isliker, Angelos Giannis, Vasilis Archontis. 2026-09-21. Current Sheet Fragmentation in the Course of Repeated Eruptive Magnetic Flux Emergence. https://arxiv.org/abs/2609.25480

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