Two types of flare-associated coronal mass ejections

Abstract

Aims. Here, we study the relationship between flares and CMEs. Methods. For this purpose a statistical analysis of 578 flare-associated CMEs is presented. We considered two types of flare-associated CMEs: CMEs that follow and precede flare onset. Results. We shown, that both samples have quite different characteristics. The first type of CMEs tends to be decelerated (median acceleration = -5.0 ms-2), faster (median velocity = 519 kms -1), and physically related to flares (a correlation coefficient between the energy of the CME and the peak of the X-ray flare = 0.80). The CMEs preceding associated flares are mostly accelerated (median acceleration = 5.4 ms-2), slightly slower (median velocity = 487 kms-1), and poorly related to flares (a con-elation coefficient between the energy of the CME and the peak of the X-ray flare = 0.12). Conclusions. These two types of flare-associated CMEs demonstrate that magnetic reconnection, which influences the CME acceleration, could be significantly different in the two types of events. © ESO 2009.