Flare Irradiance Studies with the EUV Variability Experiment on SDO R. A. Hock, F. G. Eparvier, T. N. Woods, A. R. Jones, University of Colorado at Boulder L. Didkovsky University of Southern California B. J. Thompson NASA Goddard Space Flight Center

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China PI: Tom Woods, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder CO All about EVE SCIENCE THEMES: 1. Specify the solar EUV spectral irradiance and its variability on multiple time scales 2. Advance current understanding of how and why the solar EUV spectral irradiance varies 3. Improve the capability to predict the EUV spectral irradiance variability 4. Understand the response of the geospace environment to variations in the solar EUV spectral irradiance and the impact on human endeavors

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Multiple EUV Grating Spectrograph (MEGS)  At 0.1 nm resolution MEGS-A: 5-36 nm MEGS-B: nm  At 1 nm resolution MEGS-SAM: 0-7 nm  At 10 nm resolution 122 nm  Ly-a Proxy for other H I emissions at nm and He I emissions at nm EUV Spectrophotometer (ESP)  At 4 nm resolution 17.5, 25.6, 30.4, 36 nm  At 7 nm resolution nm (zeroth order) Solar Aspect Monitor (SAM)  nm image All about EVE

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China All about EVE First light EVE spectrum with AIA & ESP bandpasses. EVE measures the spectral EUV irradiance from nm with 0.1 nm spectral resolution a 10-second time cadence.

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Temperature Coverage of EVE Peak formation temperature from CHIANTI vs. wavelength for bright lines in a EVE spectrum (quiet Sun)

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Active Region Evolution Sub-daily variations in EUV lines are associated with AR evolution and small flares 5% 3%

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Solar Activity during Year 1 Levels of solar activity during the first year of SDO observations

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Space Weather & Flare Location Space Weather products are available from

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China...not just flares anymore ✴ EVE is proving to be a remarkable instrument for understanding the global nature of EUV irradiance variability ✴ Future work will focus on moving from qualitative study of the EUV irradiance variability to quantitative study 2048 pixels 1024 pixels

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Coronal Dimmings Coronal dimming seen in both AIA 171 channel and EVE 17.1 nm line

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Radiative Output of Solar Flares Four M1.0 flares have significantly different light curves in the EUV. EVE allows us to quantify how the corona cools after a flare.

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Flare Classification

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Compact Flares C2.2 on 25 October 2010 ✴ Non-eruptive ✴ Cohesive group of loops brighten concurrently

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Localized Eruptive Flares C4.6 on 12 November 2010 ✴ Localized brightening associated with EUV surges ✴ Occurs at the edge of an AR at the footpoint of a loop that connects to a different part of the AR or to another AR entirely. ✴ Possibly the Skylab point flares previously categorized with compact flares

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Arcade Flares C2.3 on 14 December 2010 ✴ Long(ish) duration events with EUV emission lasting hours ✴ Generally associated with filament eruptions & coronal dimmings ✴ Arcade of post-flare loops in corona and 2-ribbon footpoints in chromosphere

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Late Phase Flares C8.8 on 5 May 2010 ✴ Two spatially-distinct but related enhancements in 2-3 MK emission tens of minutes to hours apart ✴ Previously observed but EVE has shown that these flares have a strong and unique irradiance signature that can account for up to 40-80% of the energy radiated in the EUV

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Example of a Late Phase Flare Comparison of AIA and EVE lightcurves & a cartoon of the evolution of the 5 May 2010 C8.8 flare

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Distribution of Flare Types

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Distribution of Flare Types

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Future Work ✴ Continue to update the flare catalog including ✴ Adding ~150 flares from March 2011 ✴ Adding association with CMEs ✴ Validating impulsive phase using RHESSI data ✴ Validating extracted parameters from EVE data ✴ Start to associate flare parameters with physical quantities: ✴ Loop length ✴ Arcade length ✴ Magnetic field strength

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Arcade Flare Irradiances Correlations of rise time in SXR with (1) flare duration, (2) delay in EUV peak irradiances, and (3) GOES magnitude

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Irradiance Flare Peak Width

ILWS-2011 Workshop "Towards the Next Solar Maximum" 30 August 2011 Beijing, China Impulsive Phase Measured by He II 30.4 nm C1.0+C4.0+