A Statistical Analysis of Deflection of Coronal Mass Ejections in the Field of View of LASCO Coronagraphs

Abstract

Coronal mass ejections (CMEs) can generate the most severe geomagnetic disturbances. One of the most critical factors affecting a CME’s geoeffectiveness is its trajectory. It is crucial to determine whether and when CME will hit Earth. It is commonly assumed that CMEs experience a deflection of propagation in the corona and in interplanetary space. In this study, we analyze more than 14,000 CMEs listed in the Coordinate Data Analysis Workshop (CDAW) catalog during 1996–2022 to estimate their deflection in the Large and Spectrometric Coronagraph field of view (LFOV). In our statistical analysis, the deflection was determined using the CME height–time measurements listed in the CDAW catalog. We have shown that, in the solar corona, CME deflection is a common phenomenon, heavily influenced by solar activity cycles as well as phases of these cycles. We have demonstrated that during periods of solar activity minima the deflection of CMEs is mostly toward the equator, and during periods of maxima it is mostly toward the poles. This general trend of deflection is further modified by the specific structure of the magnetic field generated during successive cycles of solar activity (e.g., the asymmetry between the hemispheres). A systematic increase in deflection with time was also recognized. We have also found that the deflection increases linearly with the distance from the Sun in the LFOV (the line slope is 0.5).