The role of active region coronal magnetic field in determining coronal mass ejection propagation direction

TL;DR

This study investigates how the magnetic field configuration of an active solar region influences the propagation direction of a coronal mass ejection, emphasizing the importance of magnetic field analysis for accurate CME trajectory prediction.

Contribution

It introduces a new CME reconstruction method and demonstrates that active region magnetic fields significantly affect CME direction, highlighting the need to consider magnetic configuration in predictions.

Findings

CME changed its direction by 28° in latitude and 43° in longitude.

Active region magnetic field strongly influences CME propagation.

Magnetic field analysis improves understanding of CME trajectories.

Abstract

We study the role of the coronal magnetic field configuration of an active region in determining the propagation direction of a coronal mass ejection (CME). The CME occurred in the active region 11944 (S09W01) near the disk center on 2014 January 7 and was associated with an X1.2 flare. A new CME reconstruction procedure based on a polarimetric technique is adopted, which shows that the CME changed its propagation direction by around 28$^\circ$ in latitude within 2.5 R$_\odot$ and 43$^\circ$ in longitude within 6.5 R$_\odot$ with respect to the CME source region. This significant non-radial motion is consistent with the finding of M$\ddot{o}$stl et al. (2015). We use nonlinear force-free field (NLFFF) and potential field source surface (PFSS) extrapolation methods to determine the configurations of the coronal magnetic field. We also calculate the magnetic energy density distributions at different heights based on the extrapolations. Our results show that the active region coronal magnetic field has a strong influence on the CME propagation direction. This is consistent with the "channelling" by the active region coronal magnetic field itself, rather than deflection by nearby structures. These results indicate that the active region coronal magnetic field configuration has to be taken into account in order to determine CME propagation direction correctly.