Solar flare-CME association

We carry out the first statistical study that investigates the flare-coronal mass ejections (CMEs) association rate as function of the flare intensity and the total unsigned magnetic flux (Φ_AR) of ARs that produces the flare. Our results show that flares of the same GOES class but originating from an AR of larger Φ_AR, are much more likely confined. This implies that Φ_AR is a decisive quantity describing the eruptive character of a flare, as it provides a global parameter relating to the strength of the background field confinement. We also calculated the mean twist values α in regions close to the polarity inversion line and proposed a new parameter α / Φ_AR to measure the probability for a large flare to be associated with a CME. We find that the new parameter α/ Φ_AR is well able to distinguish eruptive flares from confined flares.