The speed of halo Coronal Mass Ejections and properties of associated active regions

In this study, we looked for any correlations between speed of active region-related halo Coronal Mass Ejections (CMEs) and the energy contained in active regions. Twenty one CMEs from the Coordinated Data Analysis Workshops (CDAW) event list are chosen to carry out this research. The solar sources of the CMEs have been carefully determined by the CDAW source identification team using various methods. This study shows that (1) there is no correlation between potential energy of active regions and the associated CMEs' speed; (2) there is no correlation between net magnetic flux of active regions and the associated CMEs' speed. Net magnetic flux of an active region is defined here as sum of the positive and negative magnetic fluxes of this active region, and may thus represent the large-scale magnetic flux that connects this active region and the remote areas. Based on a limited sample of eight events that could be adequately modeled for analysis of free energy of the active regions, this study further shows that there is a correlation between free energy density of active regions and speed of the associated CMEs.