An Automated Methodology for Associating Solar Flares and Coronal Mass Ejections during Energetic Solar Eruptive Events
Bill Swalwell
Jeremiah Horrocks Institute, University of Central Lancashire
Silvia Dalla (jeremiah Horrocks Institute), Robert Walsh (Jeremiah Horrocks Institute)
Solar Flares with high levels of energy emission in soft X-rays frequently occur in spatial and temporal association with a Coronal Mass Ejection (CME). Together these phenomena are the drivers of a variety of space weather effects. Understanding the link between flares and CMEs is vital. The association of a CME with a solar flare is often used to pinpoint the active region on the Sun where the CME originated. However, making those associations is labour-intensive and involves some degree of subjectivity. Here we present a methodology which allows such associations to be made automatically for energetic eruptive events, defined as events in which the flare intensity is above M5 and/or the CME speed exceeds 1,000 km/s. The method is intended to be used for scientific analysis of a large sample of events. To develop the method we analysed a period of 13 months around solar maximum in solar cycle 24. We selected all energetic events and manually associated flares (as reported by the GOES SXR list) and CMEs (identified in the CDAW catalogue) by studying images and movies taken by the LASCO C2 coronagraph and SDO AIA. We then implemented an automated method which can reproduce the manual associations in 94% of cases by a simple temporal association requirement. Our analysis has also shown that, for energetic events in the selected period, in all cases the flare starts before the first observation of the CME.