Three‐dimensional magnetic reconnection and the magnetic topology of coronal mass ejection events

TLDR

The study proposes that 3‑dimensional reconnection near the Sun explains the occurrence of singly‑connected field lines in coronal mass ejections. The authors attribute these field lines to 3‑dimensional reconnection occurring close to the Sun. Observations reveal that most CME field lines are double‑connected to the Sun, but some are singly‑connected, and the proposed reconnection model accounts for both the flux‑rope topology of CMEs and the presence of field lines connected to the outer heliosphere at both ends.

Abstract

Measurements of suprathermal electron fluxes in the solar wind indicate that field lines within coronal mass ejections, CMEs, near and beyond 1 AU are normally connected to the Sun at both ends. However, on occasion some field lines embedded deep within CMEs appear to be connected to the Sun at only one end. Here we propose an explanation for how such field lines arise in terms of 3‐dimensional reconnection close to the Sun. Such reconnection also provides a natural explanation for the flux rope topology characteristic of many CMEs as well as the coronal loops formed during long‐duration, solar soft X‐ray events. Our consideration of the field topologies resulting from 3‐dimensional reconnection indicates that field lines within and near CMEs may on occasion be connected to the outer heliosphere at both ends.