Analyzing deflection of multiple Solar Coronal Mass Ejections from the same active region

Abstract

The deflection of Solar Coronal Mass Ejections (CMEs) near the Sun may be the consequence of interaction between a CME and a coronal hole or the solar wind (Gopalswamy et al., 2009a, 2009b). In this study, 124 halo-CMEs that originate from 40 active regions are analyzed to deduce whether multiple CMEs from the same active region are deflected in the same direction, as well as to find the accuracy of predicting the deflection direction of a CME according to the ambient large-scale magnetic field configuration. It was found that at least 73% (29 groups) were significantly deflected. Also of the 16 groups with multiple significantly deflected CMEs from the same active regions, the deflection direction for the CMEs in 88% (14 groups) was consistent with each other. The magnetic field configuration was computed from synoptic maps of magnetic field from SOHO/MDI and SDO/HMI using a Potential Field Source Surface (PFSS) model. We have performed the error analysis for the calculation of the ambient magnetic field. After excluding the cases with high error, of the remaining 23 significantly deflected groups, the deflection of 91% (21 groups) was consistent with the ambient magnetic field configuration. Among them, 86% of the groups were deflected toward the Heliospheric Current Sheet (HCS), the boundary between the magnetic field polarities, and 14% toward Pseudo-Streamers (PS), the boundary between the same-polarity magnetic field regions. It was found to be in good agreement with previous studies.