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arXiv · 2607.14043

Observational Evidence for Counter-helicity Magnetic Reconnection in a Solar Eruption

Jinrui Chang·Yi Bi·Bo Yang·Junchao Hong·Jiayan Yang·Qingmei Wang
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Abstract

Magnetic reconnection between coronal magnetic systems carrying opposite self-helicity may play a role in solar eruptions, but observational evidence remains limited. We investigate an M7.0 flare in NOAA Active Region 13615 on 2024 March 28 using multiwavelength observations and nonlinear force-free field extrapolations. The reconstructed coronal field reveals a low-lying positive-helicity core field beneath an overlying magnetic system of opposite sign. During the eruption, the footpoint connectivity of these two magnetic systems changes markedly: field lines rooted in the western footpoint region change from positive to negative helicity, and the positive-helicity domain is substantially reduced. These changes are accompanied by a remote chromospheric brightening, intermittent EUV stripe-like brightenings extending from the source region toward the remote chromospheric brightening, the subsequent formation of large-scale coronal loops, and a weak outer hard X-ray source located at a footpoint of the core field. Together, these results suggest that the eruption was closely associated with reconnection between the core field and the overlying counter-helicity system, providing observational evidence that counter-helicity reconnection can contribute to the destabilization of eruptive solar magnetic fields.

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Jinrui Chang, Yi Bi, Bo Yang, Junchao Hong, Jiayan Yang, Qingmei Wang. 2026-07-15. Observational Evidence for Counter-helicity Magnetic Reconnection in a Solar Eruption. https://arxiv.org/abs/2607.14043

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