TSI and VUV Radiative Energies During X-Class Solar Flares Chris Moore Undergraduate Student U. of Iowa (2 summers at LASP/U. Of Colorado) Phillip Chamberlin, Rachel Hock, Greg Kopp LASP/U. of Colorado 8/14/2015Moore - Onset of SC 24

Research Objectives Analyzing the energy contribution of solar flares, in the VUV, soft/hard X-rays and the microwave wavelengths. Finding the energy composition from the impulsive and gradual phase of each spectral region Search for a center to limb variation

Impulsive and Gradual phases Neupert effect (1968) + =

8/14/2015Moore - Onset of SC 24 The Flare Irradiance Spectral Model (FISM) FISM is an empirical model of the solar vacuum ultraviolet (VUV; nm) irradiance at 60 second temporal resolution. Phil Chamberlin developed for his Ph.D. Dissertation (U. of Colorado, 2005) Current version released June 2008 – Updated for SEE V9 data Uses traditional proxies (MgII c/w, F10.7, and Ly  ) as well as new proxies (0-4 nm, 36.5 nm, and 30.5 nm) to model the daily component - provide more accurate CLV. Uses the GOES nm irradiance as the proxy to model flare variations. FISM is the first flare model that can be used for near real-time space weather operations.

8/14/2015Moore - Onset of SC 24 Solar Variation on Various Time Scales EUV irradiance increased by a factor of 2 and XUV increases by a factor of 100 during the gradual phase Transition region emissions increased by up to a factor of 10 during the impulsive phase Flare Variations were as large or larger than the solar cycle variations for the Oct 28, 2003 flare

8/14/2015Moore - Onset of SC 24 TSI Flare Budget - Revisited Reanalysis of TSI and VUV spectral contributions from Woods, Kopp, and Chamberlin, JGR, 2006 Updated using V9 TIMED SEE data – Lower contributions from nm (/10) – Revised spectral distribution Better TSI fitting algorithm Addition of RHESSI Contribution Have run analysis for 21 April 2002 and 23 July 2002 events (Emslie, Dennis, Holman, and Hudson, JGR, 2005) Using TSI “Model” –NOTE: Very limited: based on 5 flares

TIM/TSI scaling  Accuracy of 100 ppm (.01%)

8/14/2015Moore - Onset of SC 24 TSI Flare Budget - Revisited October 28, X17 - (E08, S16) November 4, X28 - (W83, S19) Numbers from WKC Also have data for 10/29/03, 11/2/03*, 1/15/05*, 1/19/05*, 1/20/05*, 9/7/05, 12/5/06*, 12/6/06, 12/13/06* * - Modeled TSI (can do for any flare, but these selected because of good RHESSI data)

TSI results  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

8/14/2015Moore - Onset of SC 24 TSI Flare Budget - Modeled Emslie, Dennis, Holman, and Hudson, JGR, 2005 Modeled the total ‘final’ radiant energy of two limb flares from GOES temperature and emission measure 21 April 2002: 3 x /- 0.3 x July 2002: 1 x /- 0.3 x New TSI Model Use the FISM energy and location on disk to estimate TSI energy released in flare 21 April 2002: 3.4 x July 2002: 3.3 x 10 31

TSI model Based on VUV, TSI can be modeled to show energy release that would have been seen during TSI eclipse periods or before TIM operation – N = # of center/limb flares seen in TSI (Take limb flares to be greater than 70º east or west) – TI = impulsive phase energy in TSI – TG = gradual phase energy in TSI – VI = impulsive phase energy in VUV – VG = gradual phase energy in VUV – FI = VI/TI = fraction of impulsive phase energy from VUV compared to TSI – FG = VG/TG = fraction of gradual phase energy from VUV compared to TSI – a = (1\N) * [∑ (from N to i =1) (FI(i))] = average fraction of impulsive phase energy from VUV – b = (1\N) * [∑ (from N to i =1) (FG(i))] = average fraction of gradual phase energy from VUV – A = 1/a = factor that can be multiplied by the observed impulsive phase VUV wavelengths to obtain an estimated value for the TSI – B = 1/b = factor that can be multiplied by the observed gradual phase VUV wavelengths to obtain an estimated value for the TSI

TSI Flares 5.17 x 10^31 (38%) 2.35 x 10^30 (41%) 1.1 x 10^ 32 (34%) 7.17 x 10^30 (46%) VUV [ nm] (% of TSI) 1.36 x 10^325.7 x 10^ x 10^ x10^31TSI Grad. PhaseImp. PhaseGrad. PhaseImp. PhaseSpectral Region 4-Nov-2003 (X28) (W83 S19)28-Oct-2003 (X17) (E08 S16) Flares (GOES Classification) (Location) 4.35 x 10^31 (34%) 5.17 x 10^30 (61%) VUV [ nm] (% of TSI) 1.28 x 10^ x 10^30TSI Grad. PhaseImp. PhaseSpectral Region 29-Oct-2003 (X10) (W10 S17) 1.07 x 10^32 ergs (72%) 8.42 x 10^30 (386%) 1.48 x 10^ x 10^30 Grad. PhaseImp. Phase 7-Sep-2005 (X17) (E77 S11) 1.83 x 10^31 (49%) 2.06 x 10^30 (23%) 3.75 x 10^ x 10^30 Grad. PhaseImp. Phase 6-Dec-2006 (X6.5) VUV [ nm] (% of TSI) TSI Spectral Region

Modeled Flares

Future Work  Search for additional spectral contributions to the impulsive and gradual phase to the TSI  RHESSI  White Light, through TRACE 1600 angstrom and WL bands  SPM 9 (VIRGO-SOHO)  Microwave wavelengths

Conclusion Valid estimates of the TSI radiated energy from flares – Very dependent on background subtraction Able to estimate TSI energies of all other flares when not observed by TIM with model – Model scales VUV values and incorporates CLV using flare location – Model only based on 5 flares - very limited statistics Looking forward to results for new solar cycle – Continuing measurements from SORCE TIM – New TSI flare measurements from GLORY TIM (launch July 2009) – New VUV flare measurements from SDO EVE (launch Mid to early 2010)

Back Up Slides

X17 Flare Comparison to SEE nm Si IV; Log(T)=4.85 8/14/2015Moore - Onset of SC 24

8/14/2015Moore - Onset of SC 24 TSI Flare Observations From Woods, Kopp, and Chamberlin (WKC), JGR, 2006

8/14/2015Moore - Onset of SC 24 EUV Variability Experiment (EVE) Launch in mid-2009 onboard the Solar Dynamics Observatory (SDO) University of Colorado / LASP Thomas N. Woods (PI) Francis G. Eparvier Gary J. Rottman Phillip C. Chamberlin University of Southern California Darrell L. Judge, Donald R. McMullin Naval Research Laboratory Judith L. Lean John T. Mariska Harry P. Warren MIT Lincoln Laboratory Gregory D. Berthiaume University of Alaska Scott M. Bailey NOAA Rodney A. Viereck Space Environment Technologies W. Kent Tobiska CU/CIRES/NOAA Timothy J. Fuller-Rowell Utah State University Jan J. Sojka

8/14/2015Moore - Onset of SC 24 How does EVE measure the EUV? Multiple EUV Grating Spectrograph (MEGS) –At 0.1 nm resolution MEGS-A: 5-37 nm MEGS-B: nm –At 1 nm resolution MEGS-SAM: 0-7 nm –At 10 nm resolution 122 nm –Ly-  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 0-7 nm (zeroth order) In-flight calibrations from ESP and MEGS- P on daily basis and also annual calibration rocket flights  nm

8/14/2015Moore - Onset of SC 24 How will EVE help VUV Flare Studies? 10 sec (0.25 sec for ESP) temporal resolution, 100% duty cycle – EVE will measure all flares with very good temporal resolution and concurrent spectral information. – Only 11 impulsive phase observations and 29 gradual phase observations at one point during the flare from TIMED SEE. Extend the solar XUV and EUV irradiance measurement set with better accuracy. Higher spectral resolution, especially for < 27nm – EVE is 0.1 nm spectral resolution from nm, 1.0 nm from nm. EVE will help determine the relationship between EUV and XUV flares. – Help refine timing of the Neupert Effect?

Solar flares effect on Earth CME’s Release energy up to 40 billion Hiroshima sized atomic bombs NOAA SWPC Particle events – Auroras Geomagnetic storms – Power grids – Airlines (rerouting for polar flights) – Disruptions GPS Radio blackouts

Dynamics of Solar Flares A magnetic flux tube emerges above the solar surface in active regions Magnetic flux tube is more buoyant than the surrounding plasma Eventually a filament of plasma is released after the stretching of the magnetic field lines reached their eruptive limit This gives rise to the two phases of the solar flare

Dynamics of Solar Flares 2 Energy is forced back into the atmosphere by magnetic reconnection, this is the energy input (Impulsive phase) It is not visible until the Transition region, the corona is not dense enough This influx of energy creates thermal heating in the atmosphere, seen in all regions This is the slow phase (Gradual phase) of the solar flare