Modeling the UV/EUV and its relevance for PROBA2 observations Margit Haberreiter Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center,

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<ul><li><p>Modeling the UV/EUV and its relevance for PROBA2 observationsMargit Haberreiter</p><p>Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center, Davos, SwitzerlandandLaboratory for Atmospheric and Space Physics, University of Colorado, USA</p></li><li><p>EUV spectrumWavelengths UV: 120 400 nmEUV: 10 120 nmContribution from the ChromophereTransition region Corona</p></li><li><p>Solar Modeling(SolMod continuation of SRPM)Multi level atoms373 ions, from H to Ni with ioncharge 25~14000 atomic levels~170000 spectral lines Statistical equation is solved to get the level populationsChromosphere and transition region for ioncharge 2: full NLTE (Fontenla et al., 2006; 2007; 2009)plus optically thin transition region linesSpherical symmetryCoronaioncharge &gt;2 optically thin, i.e. collisions and spontaneous emissionLine of sight integration accounts for opacitySpherical symmetry</p></li><li><p>Masks from Precision Solar Photometric TelescopeDisk mask on 2005/9/12 obtained from PSPT data, Mauna Loa, Hawaii (R) Sunspot Penumbra(S) Sunspot Umbra(P) Faculae(H) Plage(F) Active network(D) Quiet network (white)(B) Intergranular CellsDetermined by the contrast as a function of the position on the diskOnly possible with respect to a normalized quiet Sun intensityContinuum, 607 nm (PICARD)Ca II 393.4, FWHM=0.27nm</p></li><li><p>FaculaePlageActive networkQuiet networkIntergranular CellsFontenla et al., 2009, ApJ 707, 482-502</p></li><li><p>G-Band of CH molecular linesFontenla et al., 2009, ApJ 707, 482-502</p></li><li><p>Violet CN BandFontenla et al., 2009, ApJ 707, 482-502</p></li><li><p>Fontenla, Curdt, Haberreiter, et al., 2009, ApJ</p></li><li><p>Modeling the EUVe.g. Fe XV 284 </p></li><li><p>Coronal modelsSRPM Models are based on Doschek (1997), ApJ, 476, 903, Singh et al., 1982, J. Astrophys. 3, 249Cranmer et al, 2007, ApJS 171, 520</p></li><li><p>Coronal lines and Bremsstrahlung</p></li><li><p>Spectrum from Corona, TR and Chromosphere</p></li><li><p>SPRM calculation versus the EVE spectrum</p></li><li><p>EVE calibration spectrum versus calculated spectrumHaberreiter and Fontenla, 2009, AIP conference seriesEVE rocket calibration flight: Chamberlin et al., 2009, GRL</p></li><li><p>Quiet Sun versus Coronal Hole</p></li><li><p>Spherical SymmetryAllows the calculation of intensities at and beyond the limb</p><p>(e.g. Haberreiter et al. 2008) </p><p>Account for corona over 2 x area of solar diskAdopted from Mihalas, 1978</p></li><li><p>Spherical symmetry</p></li><li><p>Spherical geometry EIT 171 </p></li><li><p>SOHO/EIT imagesHe II 30.4 nmFe XV 28.4 nmFe IX 17.1 nmFe XII 19.5 nm</p></li><li><p>EIT wavelengthsEVE spectrumSRPM calculation</p></li><li><p>EIT passbandsFe IX 17.1 nm</p><p>Fe XII 19.5 nm</p><p>Fe XV 28.4 nm</p><p>He II 30.4 nm</p></li><li><p>He II 30.4 nm high resolution</p></li><li><p>Optical depthFe XV 17.1 nm: Disk center: max = 0.06Limb: (r=1.02):max = 0.63 (~900,000K)</p><p>Fe XV 19.5 nm: Disk center: max = 0.06Limb: (r=1.02):max = 0.34 (~1,100,000K)</p><p>Fe XV 28.4 nm: Disk center: max = 0.39Limb: (r=1.02):max = 0.88 (~2,000,000K)</p></li><li><p>LYRA passbandsLYRA CH 3: 17-80 nmLYRA CH 4: 6-20 nm</p></li><li><p>LYRA measure-ments April 2010Courtesy, Ingolf Dammaschs</p></li><li><p>LYRA measure-ments May 2010Courtesy, Ingolf Dammaschs</p></li><li><p>Understand the daily variations of the UV/EUVDetermine the solar cycle variation of solar activity features (with an emphasis on coronal holes) create masks similar to PSPT masksModel the variation of the solar spectrum in the EUVIs there a long-term trend of the solar spectral irradiance (due to coronal holes)</p></li><li><p>Questions to addressUnderstand the spectral variability</p><p>Do all the spectral lines behave similarlyORIncrease of line strength of some lines and a decrease of others?</p><p>Is a decrease in the EUV responsible for the decrease in TSI for the current minimum</p></li><li><p>1. Variability of solar activity featuresEIT 17.1nm07/01/2005</p><p>EIT 19.5 nm10/01/2002</p><p>EIT 28.4 nm10/10/2003EIT 30.4 nm07/10/2006</p><p>coronal holes quiet Sun quiet coronal network active coronal network - hot loop super hot loop</p></li><li><p>EIT image analysisRadial dependence for outer coronaThresholds based on intenstiy histogram of the EIT imagesMaximum value of histogram varies with solar cycle (in particular for 284 )Coronal hole intensity changes with solar cycle (Barra et al., 2009) identification of coroanl features not trivial</p></li><li><p>Area coverage of featuresData from Barra et al, 2009 </p></li><li><p>3. Determine the long-term trend of the solar spectral irradianceThe SOHO/SEM measurements indicate a decrease in the EUV by15%</p><p>Uncertainty ~ 6%</p><p>Not explained by F10.7 or sunspot number</p><p>What is the role of coronal holes?Didkovsky et al., 2009</p></li><li><p>ConclusionsGood agreement between the synthetic spectra and the observed EVE quiet Sun spectrumAn enourmous amount of spectral lines is contained in broader spectral bandsStrong interest in SWAP images for the reconstruction of LYRA observations</p></li><li><p>Questions?</p><p>*******************</p></li></ul>


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