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

Abstract Magnetic reconnection between emerging magnetic flux and the ambient coronal field fundamentally drives solar jets. We use 3D 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 f ≃ 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 ∼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.