Presentation on theme: "13. Flare Classification in the Era of Global Coverage of the Sun A. Vourlidas, C. Cohen The GOES SXR characterization of solar flares has been used widely."— Presentation transcript:
13. Flare Classification in the Era of Global Coverage of the Sun A. Vourlidas, C. Cohen The GOES SXR characterization of solar flares has been used widely for 2 solar cycles. But we now have many SEP events associated with far-side flares observed by EUV imagers only (STEREO). –360 deg coverage of the Sun will extend until 2019 or so. We invite discussion on the following aspects: How can we relate those observations to events on the front side or to previous work? Are EUV imaging observations a suitable proxy for the GOES SXR classification? –Should we use total irradiance or flux integrated over the event only? –Are other quantities (i.e., total emission measure, DEM) better proxies? Why are there differences in the SXR and EUV light profiles of flares? –Are certain event types (e.g., large flares, SEP-associated, radio-loud or quiet) better correlated in their EUV/SXR profiles? Which quantity (flare SXR class, rise-to-peak, total duration, etc) is more useful for in-situ and other studies?
Flare-CME Statistics: Flare perspective Kay et al (2003): Flare Study – Flares with CMEs have longer duration, higher peak T, lower rise – Sample: 48 CME, 21 non-CME SXR Peak Temperature vs Peak Intensity SXR Peak Intensity vs Flare duration Flare Rise Time vs Decay Time
Flare-CME statistics: CME perspective Vršnak et al (2005): Kinematic study. – No bimodal distribution found (speed or acceleration). – Continuous spectrum of events – Wider CMEs are faster – Weak-flare (B,C) CMEs similar to non-flare CMEs Velocity vs SXR Peak Flux Velocity vs CME Width Black: M,X Grey: < M
The events shown below are some examples of “structured” events. In this family of events, the x-ray signal looks typical, similar to the “classical” flare, but the EUV signal has structure in it. The EUV shape does not follow the x-ray shape, and typically has multiple peaks. Slides provided by D. Mcmullin
The events shown on this page show a strong x- ray event with little or no corresponding EUV event. Also to note, the x-ray flare in these events is somewhat slower to peak, peak at a slightly lower value, but last for a relatively long time. Slides provided by D. Mcmullin
In these events, Timing is different between the x-ray event and the EUV event, or the shapes are unusual. The lower right panel shows surprising symmetry in the x-ray signature. Slides provided by D. Mcmullin Flare Rise Time vs Decay Time
Jan 17, 2010: A case for perpendicular diffusion? SPD-2011, A. Vourlidas7 Courtesy of N. Dresing No clear anisotropy No clear velocity dispersion Electrons arrive late