On the occurrence and the motion of fast impulsive coronal mass ejections associated with powerful flares and unassociated with eruptive filaments

Abstract

The formation and initial stage of the motion of several rapid, impulsive coronal mass ejections of the “halo” type (HCME) associated with flares of M and X class, but unassociated with the eruption of solar filaments, was studied using GOES-12/SXI, SOHO/EIT, and SDO/AIA data. The HCMEs considered can be divided into three groups according to the features of their formation: (i) some HCMEs arise due to an imbalance of single emission looped structures observed in the 195 A channel of an EIT instrument for several hours before the first recording of mass ejection in the field of view of an SXI X-ray telescope, and after the eruption, these loops become structural elements of HCMEs; (ii) HCMEs can be formed as a result of an imbalance of several loops in the process of combining these loops into a single structure; and (iii) HCME formation begins with the upward motion of the group of coronal loops observed using the AIA data first in the “hot” 131 A channel, a few minutes later in the “cold” 211 A channel, later in the 193 A channel, and, finally, in the 171 A channel. The action of moving looped structures on the overlying regions of the corona leads to the formation and the motion of the frontal structure of HCMEs with increased brightness. In this case, these eruptive loops do not become structural elements of HCMEs. All investigated HCMEs began their translational motion before the occurrence of the associated flares. According to the results of studying the kinematics of the considered HCMEs we concluded that there are two types of coronal mass ejections differing according to the time profile of the velocity, which is determined by the area and the magnetic configuration of the active region where the mass ejection was formed. It is shown that HCMEs occurring at different times in the same active region have the same type of velocity profile.