Signatures of Interchange Reconnection: STEREO, ACE and Hinode Observations Combined

TL;DR

This study combines multi-spacecraft observations to investigate interchange reconnection during a solar eruption, revealing how magnetic topology influences the structure and signatures of the resulting interplanetary coronal mass ejection.

Contribution

It provides new observational evidence linking interchange reconnection to the formation of anemone structures and the magnetic topology of CMEs within coronal holes.

Findings

Identification of the eruption's emergence time and structure type from in-situ data.

Observation of an ICME with open magnetic topology passing ACE.

Evidence of interchange reconnection leading to disconnected CME legs and uni-directional electron flux.

Abstract

Combining STEREO, ACE and Hinode observations has presented an opportunity to follow a filament eruption and coronal mass ejection (CME) on the 17th of October 2007 from an active region (AR) inside a coronal hole (CH) into the heliosphere. This particular combination of `open' and closed magnetic topologies provides an ideal scenario for interchange reconnection to take place. With Hinode and STEREO data we were able to identify the emergence time and type of structure seen in the in-situ data four days later. On the 21st, ACE observed in-situ the passage of an ICME with `open' magnetic topology. The magnetic field configuration of the source, a mature AR located inside an equatorial CH, has important implications for the solar and interplanetary signatures of the eruption. We interpret the formation of an `anemone' structure of the erupting AR and the passage in-situ of the ICME being disconnected at one leg, as manifested by uni-directional suprathermal electron flux in the ICME, to be a direct result of interchange reconnection between closed loops of the CME originating from the AR and `open' field lines of the surrounding CH.