Temperatures of Large Solar X-ray Events and Associated CME Speeds
2019 July 22
Recently we  repeated an earlier analysis by [2,3] showing that large (> M3) solar X-ray flares associated with solar energetic particle (SEP) events have significantly lower peak X-ray flux ratios R of 0.04-0.5/0.1-0.8 nm, proxies for flare peak temperatures, than those without SEP events. Since we expect SEP events to be produced by shocks ahead of fast coronal mass ejections (CMEs), this would imply that an X-ray flare of a given peak flux is more likely to have a fast CME and associated SEP event when it has a relatively smaller R. We examine the role played by the ratios R in correlations between X-ray peak flare fluxes and CME speeds Vcme, and then compare CMEs widths W, speeds Vcme, X-ray flare durations ΔT, and R with each other. We resolve the apparent conflict between a global scaling model of eruptive events showing Vcme scaling with higher R and our confirmation that the [2,3] analysis implies faster CMEs are associated with flares of lower R.