Pre-Eruptive Magnetic Reconnection within a Multi-Flux-Rope System in the Solar Corona

TL;DR

This study investigates the formation and evolution of flux ropes in the solar corona, revealing that magnetic reconnection within a system of braided flux ropes plays a key role in CME initiation and complexity.

Contribution

It provides new insights into pre-eruptive magnetic reconnection within multi-flux-rope systems, enhancing understanding of CME core structures and their origins.

Findings

Reconnection occurs within a system of multiple braided flux ropes.

Complex ejecta can originate from coherent flux rope systems.

Internal flux rope dynamics are crucial for CME prediction.

Abstract

The solar corona is frequently disrupted by coronal mass ejections (CMEs), whose core structure is believed to be a flux rope made of helical magnetic field. This has become a "standard" picture although it remains elusive how the flux rope forms and evolves toward eruption. While 1/3 of the ejecta passing through spacecrafts demonstrate a flux-rope structure, the rest have complex magnetic fields. Are they originating from a coherent flux rope, too? Here we investigate the source region of a complex ejecta, focusing on a flare precursor with definitive signatures of magnetic reconnection, i.e., nonthermal electrons, flaring plasma, and bi-directional outflowing blobs. Aided by nonlinear force-free field modeling, we conclude that the reconnection occurs within a system of multiple braided flux ropes with different degree of coherency. The observation signifies the importance of internal structure and dynamics in understanding CMEs and in predicting their impacts on Earth.