Phillip Chamberlin NASA Goddard Space Flight Center Solar Physics Laboratory Greenbelt, MD USA

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1 Phillip Chamberlin NASA Goddard Space Flight Center Solar Physics Laboratory Greenbelt, MD USA With important contributions from Ryan Milligan (QUB), Daniel Ryan (ROB), Jan Sojka (USU), and the entire EVE team

2 Outline Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE) Instrument Overview Updated Observing Plan EVE Data Products and FISM Solar Flare Physics Solar Flare Introduction Radiated Energy Budget Flare cooling rate Continua and line emissions Aeronomy Impact EUV energy deposition in Upper atmosphere EVE/TDIM study of flare influence on Ionosphere Miniature X-ray Solar Spectrometer (MinXSS) Mars Atmosphere and Volatile Experiment (MAVEN) EUV Instrument Additional Highlights October 15, 2014 SCOSTEP Chamberlin 2

3 EUV Variability Experiment (EVE) To measure and model the solar EUV irradiance variations due to flares (seconds), solar rotation (days), and solar cycle (years) The Key Components of EVE EUV Spectrograph (ESP) Multiple EUV Grating Spectrograph (MEGS) 0.1 nm resolution, 10sec MEGS A, nm SAM (Solar Aspect Monitor), 0-7 nm pinhole imager MEGS B, nm MEGS-P, nm broadband *SAM ** MEGS-P ESP * MEGS A MEGS B ** October 15, 2014 SCOSTEP - Chamberlin 3

4 EVE Data Products Level Algorithm purpose Scientifically Useful Description File Duration Daily Volume (MB) 0A Fast validity check No TLM consistency/quality checking ~1 minute B Assemble images, detailed data verification No Data checks for CRC and pixel parity, parse data packets, merge image data, separate by science channel and filter wheel position ~1 minute C Space Weather Yes Quick-look indices, MEGS-A, MEGS-B, SAM, MEGS-P & ESP 1 minute 36 1 Apply calibration Yes (SAM, ESP, MEGS-P) Use measurement equations to produce irradiance units 1 hour Re-grid, extract lines Yes Bin data to fixed wavelength scale, integrate over emission features with background removal 1 hour Daily average Yes Merge all component data into daily averages, bin to 0.1 and 1 nm 24 hours October 15, 2014 SCOSTEP - Chamberlin 4

5 Flare Irradiance Spectral Model (FISM) EVE measurements will be used to update FISM (Version 2) Especially important now with EVE instrument issues Will be available through LISIRD mid-2015, as well as FISM-P Daily Model: * L4 XPS (0.1-6 nm), ESP, MinXSS? * L3 SDO/EVE/MEGS (0.1nm) ** ** L3 TIMED/SEE UARS/SORCE SOLSTICE Flare Model: * L2 SDO/EVE/MEGS (0.1nm) **?UARS/SORCE SOLSTICE? L1/L3 TIMED/SEE/EGS October 15, 2014 Chamberlin 5

6 Solar Flare EUV Emissions Using a flare cartoon from Shibata and Magara (2011) to explain EVE emissions during solar flares. Strong chromospheric and transition region emissions during impulsive phase, large coronal emissions during gradual phase Shibata and Magara (2011), using adaptations from Magara et al. (1996) and others references within. Chamberlin et al. (2013). October 15, 2014 SCOSTEP - Chamberlin 6

7 EUV Radiated Energy Budget Almost 100% duty cycle for MEGS-A, 10- sec cadence, and <15% accuracies allow for quantification of VUV radiated energies during solar flares. MEGS-B, with reduce duty cycle, has still observe 17 X-class and ~200 M-Class flares. Chamberlin et al. (2013) demonstrated this technique, and also showed that flare energy is just as (or even more?) dependent on duration rather than maximum October 15, 2014 SCOSTEP - Chamberlin 7

8 Solar Flare Cooling Using a broad range of emissions observed by EVE, a cooling rate can be determined. D. Ryan et al. (2013) looked at this cooling rate and determined the additional energy released during the flare based on the Cargill theoretical cooling rate. Additional heating of 2x10 28 to 5x10 30 ergs. October 15, 2014 SCOSTEP - Chamberlin 8

9 EVE Continua and Line Increases For the first time, He and H free-bound continua, free-free continua, and bound-bound emission lines are observed simultaneously and continuously, and presented in Milligan et al. (2014). October 15, 2014 Chamberlin 9

10 Flare Continua and Line Increases For the first time, He and H free-bound continua, free-free continua, and bound-bound emission lines are observed simultaneously and continuously, and presented in Milligan et al. (2014). Time series and total radiated energy can be computed and compared between these and measurements from other instruments (RHESSI, SDO/AIA, HINODE SOT) see paper for results. October 15, 2014 Chamberlin 10

11 Energy Deposition in the Upper Atmosphere Stan Solomon has calculated the energy deposition in the upper atmosphere using cross sections and solar spectra, both before and during a flare. October 15, 2014 Chamberlin 11

12 Energy Deposition in the Upper Atmosphere Stan Solomon has calculated the energy deposition in the upper atmosphere using cross sections and solar spectra, both before and during a flare. October 15, 2014 Chamberlin 12

13 Solar Flare Influence on Ionosphere Sojka et al (2013) used EVE and FISM solar flare data to drive the Utah State University time-dependent ionosphere model (TDIM). Actual EVE data for X1.6 flare March 9, 2011, scaling of EVE using FISM scaling for X28 (Nov 4, 2003) and X17 (Oct 28, 2003) flares. October 15, 2014 Chamberlin 13

14 Miniature X-ray Solar Spectrometer (MinXSS) 3U CubeSat developed by U. of Colorado, LASP PI: Dr. Tom Woods Launch in mid-2015 for nominal 6-month mission Justification: Need accurate measurements of solar soft X-ray spectral irradiance from 0.1-6nm Currently and historically only broadband. Currently use models to get solar spectral distribution (e.g. CHIANTI, Woods et al., 2008) Flare energy peaks around 2 nm, but spectral distribution is highly variable. Shouldn t use a static spectrum. Spectral distribution of energy greatly influence energy deposition and heating rates in the E-region. Also spectral distribution would influence secondary ionizations. Jan Sojka used scaled 0.1-5nm EVE results to look at influence of of this solar spectral region. From Sojka et al., 2013 October 15, 2014 Chamberlin 14

15 Mars Atmosphere Volatile Experiment EUV instrument as part of the Langmuir Probe and Waves Remote Sensing package Opens door for first light and calibrations in late Oct. Three channels to provide proxy inputs for FISM, representing three layers of the solar atmosphere: Lyman-Alpha, nm (Transition Region), 17.1 nm (Cool Corona), and 0-6 nm (Hot Corona) SDO EVE (via FISM) is critical to these results. Provide EUV energy inputs to Martian system at Space Weather time scales, then extrapolate back in time. October 15, 2014 SCOSTEP - Chamberlin 15

16 Mars Ionosphere response to a solar flare Lollo et al. (2012) has looked at the flare response in the ionosphere of Mars with MGS as well as developed an ionospheric model. The 110 km peak (produced by X-Rays) exceeds the 140 km peak (produced by EUV) during a flare. The red line on the right corresponds temporally to the blue line on the left, both at 14:16 UT. Plots courtesy Paul Withers, 2007 Mars Global Surveyor Radio Science Instrument October 15, 2014 SCOSTEP - Chamberlin 16

17 Additional Highlights Moore et al. (2013): TSI flare energy quantification and empirical model Chamberlin et al. (in preparation) and Hudson et al. (2011): Doppler Shifts observed with EVE Woods et al. (2011, 2014): Late phase of solar flares Many other papers looking at the source of this late phase Mason et al., (2014): Coronal Dimming during flares Warren (2014): Abundances in solar flares Hock et al., (2013): Level 0C data is backup for GOES XRS Milligan et al., (2012): Flare density diagnostics Huang et al., (2014): Flare wavelength dependence on upper atmosphere Peterson et al., (2013): Photoelectron production at Earth and Mars Emslie et al., (2012): Global energetics of large solar flares Qian et al., (2012): Solar flare impacts on ionospheric electrodynamics and many more! October 15, 2014 Chamberlin 17

18 Conclusions Although main purpose of EVE was to accurately quantify soft X-ray and EUV inputs to the Ionosphere/Thermosphere system, EVE has had significant input into Solar Physics studies. Demonstrate power of collaboration between multiple instruments/teams EVE data is available and being used by the many scientists in the aeronomy and space weather community. From studies of solar flare to solar cycle influences, or to remove noise Just above solar surface (chromosphere) to just above Earth s surface (~80 km) Almost Sun-to-Mud. EUV variability is driven by processes within Sun, and through ionospheric influence and global electric circuit that drives ground-level effects. EVE, and FISM, can provide significant input to VarSITI With start of new program, good time for new focus to move away from F10.7 to actual spectral soft X-ray, FUV, and EUV measurements and, when not available, models that are based on more representative proxies. Its not just Sun to mud, but EUV influences other bodies. Thank You! October 15, 2014 Chamberlin 18

19 Back-up Slides October 15, 2014 SCOSTEP - Chamberlin 19

20 TSI Modeling C. Moore et al. (2013) was able to use FISM algorithms to produce an empirical model of TSI emission for flares using GOES and SORCE/TIM. These results can be separated into impulsive and gradual phase emissions via GOES XRS and its d/dt, but are very dependent on background subtraction October 15, 2014 Chamberlin 20

21 TSI Modeling Results (2) C. Moore et al (2013) was able to use FISM algorithms to produce an empirical model of TSI emission for flares using GOES and SORCE/TIM. Impulsive Phases Oct. 28, 2003 (X17) 1.56 x 10^31 ergs Oct. 29, 2003 (X10) 8.54 x 10^30 ergs Nov. 4, 2003 (X28) 5.7 x 10^30 ergs Sep. 7, 2005 (X17) 2.18 x 10^30 ergs Dec. 6, 2006 (X6.5) 8.83 x 10^30 ergs Gradual Phases Oct. 28, 2003 (X17) 3.46 x 10^32 ergs Oct. 29, 2003 (X10) 1.28 x 10^32 ergs Nov. 4, 2003 (X28) 1.36 x 10^32 ergs Sep. 7, 2005 (X17) 1.48 x 10^32 ergs Dec. 6, 2006 (X6.5) 3.75 x 10^31 ergs October 15, 2014 SCOSTEP - Chamberlin 21