Angela Colman and Richard Canfield recently completed a statistical study relating eruptive solar flares to a pre-flare phenomenon dubbed moving blue shift events (BSEs). BSEs are interpreted as being the result of magnetic reconnections in the chromosphere. They studied 16 solar flares that were well observed by the Mees Imaging Spectrograph in Hawaii and the Yohkoh spacecraft for three hours prior to each flare. From their study, they determined that the average rate of BSEs was five times greater for eruptive flares than for non-eruptive flares, and that the rate of BSEs was six times greater in the three hours before an eruptive flare than afterwards. This indicates that magnetic reconnections in the chromosphere do indeed play a role in solar flare eruptions.
I have extended this study of BSEs from three hours before the flare to several days before the flare. The number of days prior to the flare available for study varied from 0 to 7. I studied two regions, both eruptive, to determine if BSEs were also present in the days before a flare. Having blue shift events present only in the hours before an eruption would indicate that these are signs of an impending eruption. If present in the several days prior to an eruption, it would indicate that the region was likely to erupt, but without any way of telling exactly when.