Analysis of Solar Eruptions Deflecting in the Low Corona: Influence of the Magnetic Environment

Abstract Coronal mass ejections (CMEs) can exhibit nonradial evolution. The background magnetic field is considered the main driver for the trajectory deviation relative to the source region. The influence of the magnetic environment has been largely attributed to the gradient of the magnetic pressure. In this work, we propose a new approach for investigating the role of topology on CME deflection and for quantifying and comparing the action between the magnetic field gradient (“gradient” path) and the topology (“topological” path). We investigate eight events simultaneously observed by the Solar Orbiter, STEREO-A, and the Solar Dynamics Observatory; and, with a new tracking technique, we reconstruct the 3D evolution of the eruptions. Then, we compare their propagation with the predictions from the two magnetic drivers. We find that the “topological” path describes the CME actual trajectory much better than the more traditional “gradient path.” Our results strongly indicate that the ambient topology may be the dominant driver for deflections in the low corona, and that this presents a promising method for estimating the direction of propagation of CMEs early in their evolution.