Two Distinct Types of CME-flare Relationships Based on SOHO and STEREO Observations

In this paper, we present two distinct types of coronal mass ejection (CME)-flare relationships according to their observing time differences using 107 events from 2010 to 2013. The observing time difference,triangle T, is defined as flare peak time minus CME first appearance time at Solar Terrestrial Relations Observatory (STEREO) COR1 field of view. There are 41 events for group A (triangle T < 0) and 66 events for group B (triangle T >= 0). We compare CME 3D parameters (speed and kinetic energy) based on multi-spacecraft data (SOlar and Heliospheric Observatory (SOHO) and STEREO A and B) and their associated flare properties (peak flux, fluence, and duration). Our main results are as follows. First, there are better relationships between CME and flare parameters for group B than that of group A. In particular, CME 3D kinetic energy for group B is well correlated with flare fluence with the correlation coefficient of 0.67, which is much stronger than that (cc = 0.31) of group A. Second, the events belonging to group A have short flare durations of less than 1 hr (mean = 21 minutes), while the events for group B have longer durations up to 4 hr (mean = 81 minutes). Third, the mean value of height at peak speed for group B is 4.05 Rs, which is noticeably higher than that of group A (1.89 Rs). This is well correlated with the CME acceleration duration (cc = 0.75). A higher height at peak speed and a longer acceleration duration of CME for group B could be explained by the fact that magnetic reconnections for group B continuously occur for a longer time than those for group A.