Quantitative Analysis of CME Deflections in the Corona

TL;DR

This study analyzes ten CME events to understand their deflections in the corona, revealing that magnetic energy density gradients primarily influence CME trajectories, with results supporting the MEDG model.

Contribution

It provides a quantitative analysis of CME deflections using the MEDG model and three-dimensional CME data, highlighting magnetic fields' role in CME propagation.

Findings

Most CMEs experienced directional changes during propagation.

Deflections correlate positively with magnetic energy density gradients.

Weak anti-correlation between deflection rate and CME speed.

Abstract

In this paper, ten CME events viewed by the STEREO twin spacecraft are analyzed to study the deflections of CMEs during their propagation in the corona. Based on the three-dimensional information of the CMEs derived by the graduated cylindrical shell (GCS) model [Thernisien et al., 2006], it is found that the propagation directions of eight CMEs had changed. By applying the theoretical method proposed by Shen et al. [2011] to all the CMEs, we found that the deflections are consistent, in strength and direction, with the gradient of the magnetic energy density. There is a positive correlation between the deflection rate and the strength of the magnetic energy density gradient and a weak anti-correlation between the deflection rate and the CME speed. Our results suggest that the deflections of CMEs are mainly controlled by the background magnetic field and can be quantitatively described by the magnetic energy density gradient (MEDG) model.