1 / 20

VI. Forecasting Solar EUV/UV Radiation – EUV spectral synthesis

VI. Forecasting Solar EUV/UV Radiation – EUV spectral synthesis. Margit Haberreiter Juan Fontenla LASP, University of Colorado Boulder, USA. Motivation. EUV/UV influences the neutral density in the thermosphere/ionosphere Influence on satallite drag

dai
Télécharger la présentation

VI. Forecasting Solar EUV/UV Radiation – EUV spectral synthesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. VI.Forecasting Solar EUV/UV Radiation – EUV spectral synthesis Margit Haberreiter Juan Fontenla LASP, University of Colorado Boulder, USA

  2. Motivation • EUV/UV influences the neutral density in the thermosphere/ionosphere • Influence on satallite drag • Aim: forecast the EUV radiation based on physical principles over a solar rotation • Focus: physics-based EUV spectral synthesis

  3. EUV spectrum • Contribution from • chromophere • transition region • corona • Input to our model: • temperature and density structures of each of these regimes for various regions on the solar disk

  4. Atmosphere structures – chromosphere Upper chromosphere Lower chromosphere Quiet Sun Quiet Netw. Active Netw. Plage Faculae Semi-empirical NLTE structures reproduce radiance observations at 1-2‘‘(Fontenla et al 2008, in prep.) The models describes the distribution of heated areas on solar disk

  5. Coronal models

  6. SRPM • Multi level atoms • 373 ions,from neutral H to Ni with ioncharge 25 • ~14’000 atomic levels • ~170’000spectral lines • Chromosphere and transition region: • for ioncharge up to 2: • full NLTE (Fontenla et al., 1999; 2006; 2007) • plus optically thin transition region lines • Corona • ioncharge >2: optically thin, i.e. collisions and spontaneous emission

  7. Extension of Corona

  8. Spherical Symmetry Spherical symmetrie: Calculation of intensities at and beyond the limb In total: 2 x area of solar disk Plane parallel: Only disk rays are calculated

  9. Fe IX 17.1 nm - disk integrated Plane parallel vs. spherical

  10. EVE rocket flight • Calibration flight on April 10, 2008 at “Solar minimum“ conditions (EVE rocket team at LASP: Tom Woods, Frank Evapier, Phil Chamberlin, Rahel Hock, a.o., Chamberlin et al., in preparation)

  11. EUV irradiance spectra

  12. EUV irradiance spectra • 0.75 Quiet Sun (B) +0.22 (Quiet Network) +0.03 Active Network (F) • Lyman continuum matches well with EVE rocket spectrum from April 10, 2008

  13. EUV irradiance spectra at instrument resolution

  14. Shorter than 50 nm coronal/upper TR lines form a pseudo continuum

  15. EUV Irradiance QS 10-40 nm

  16. EUV radiance spectra of quiet Sun • 0.75 Quiet Sun (B) +0.22 (Quiet Network) +0.03 Active Network (F) • Good agreement with average QS (SUMER Atlas, Curdt et al.)

  17. Masks of active regions Solar maximum: September 22, 2001 Solar minimum: April 10, 2008

  18. EUV spectrum Active Sun

  19. Conclusions • The vast number of spectral lines have to be included • Due to the extension of the corona spherical symmetry is essential for coronal lines • SRPM EUV spectra agree well with EVE rocket irradiance spectrum and SUMER radiance spectra

  20. Future plans • Validation against more EUV observations • include coronal holes and active region loops in the calculation of the spectrum • Produce daily EUV/UV spectra • changing distribution of coronal features, e.g. coronal holes, active region loops • Apply the forcasting scheme as shown before

More Related