Peak Temperatures of Large Solar X-Ray Flares and Associated CME Speeds and Widths

Abstract

We recently repeated an earlier analysis by Garcia showing that large (≥M3.0) solar X-ray flares associated with solar energetic particle (SEP) events have significantly lower peak X-ray flux ratios R  = (0.04–0.5 nm)/(0.1–0.8 nm), proxies for flare peak temperatures, than those without SEP events. As we expect SEP events to be produced by shocks ahead of fast coronal mass ejections (CMEs), a smaller R for an X-ray flare of a given peak flux Fp should also be more likely to be accompanied by a fast ( V cme > 1000 km s −1 ) CME. We confirm this expectation, examine the role played by the ratios R in correlations between Fp and CME speeds V cme, and then compare CME widths W , V cme, and R with each other. We consider an apparent conflict between a global scaling model of eruptive events showing V cme scaling with higher R and our confirmation that the Garcia analysis implies that faster CMEs are associated with flares of lower R . The R values are examined for 16 large flares of the well-studied AR 12192, for which nearly all flares had no associated CMEs. Those flares share the same high values of R as other active region (AR) flares with no CMEs. We also find that small (