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The Sun and Space Weather

Arnold Hanslmeier Institut für Physik/Geophysik, Astrophysik und Meteorologie. Graz arnold.hanslmeier@kfunigraz.ac.at. The Sun and Space Weather. The Sun, the star we live with …. Basic facts: G2V star T Surface: 5800 K center: 15 000 000 K Age: 4.5 Billion years 150 000 000 km

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The Sun and Space Weather

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  1. Arnold Hanslmeier Institut für Physik/Geophysik, Astrophysik und Meteorologie. Graz arnold.hanslmeier@kfunigraz.ac.at The Sun andSpace Weather

  2. The Sun, thestarwe live with… • Basic facts: • G2V star • T • Surface: 5800 K • center: 15 000 000 K • Age: 4.5 Billion years • 150 000 000 km distance • Constant star ???

  3. Concept: basicequationsfor stellar structure

  4. Informationaboutthe Sun

  5. Helioseismology

  6. Structureofthe Sun

  7. Rotation

  8. Thermonuclearreactions

  9. Testingthe solar interior: Neutrinos

  10. Observingthe Sun…

  11. Solar granulation Earth

  12. The quiet Sun –convectiveovershoot KolmogorovTheoryofisotropic turbulence 2-D Powerspectra: Velocity ~ k-5/3 Intensity ~ k-5/3 k<kc ~ k-17/3 k>kc Kc separates convective fromdiffusiverange

  13. Solar granulation

  14. Questionstobeanswered • Variation with solar activity cycle  Observatoire Pic du Midi, Univ. Toulouse • Generation of acoustic flux and its relation to shocks and turbulence  Instituto de Astrofisica de Canarias, Tatranska Lomnica, Kiepenheuer Institut, Univ. of Colorado, Univ. of Chicago • 3-D HD and MHD simulations  Univ. of Vienna, Univ. of Colorado

  15. Sunspots – indicatorfor solar activity

  16. Sunspots Umbra: T 4000 K Penumbra: T 5500 K Photosphere: T 6000 K

  17. Zeemansplitting Sunspots: strong magnetic Fields – Umbra: vertical Penumbra: horizontal

  18. The surface intensity shows the sunspot with the dark central umbra surrounded by the somewhat brighter, filamentary penumbra. The second plane cuts from the surface to 24000 km deep showing areas of faster sound speed as reddish colors and slower sound speed as bluish colors. The third plane (bottom) is a horizontal cut at a depth of 22000 km showing the horizontal variation of sound speed.

  19. Wheredoesmagneticfluxappear on the solar surface?

  20. Solar Dynamo a w Dynamo Coriolis, convection Diff. Rotation

  21. Howcan a starbecomeactive? • Magnetic field • Convection zone – surface • Magnetic buoyancy • Differential rotation •  Stellar dynamo •  Intermittency??

  22. Who’s active, Who’s not Evidence of magnetic activity Activity on main sequence: types F  M B-V > 0.4

  23. Attheonsetofcycle 24 Sunspotdeficitcompensation

  24. Complexityofactiveregions Tachocline Magneticflux Photosphere Sunspots, bipolar groups Chromosphere Faculae, Flares Corona CMEs, Solar Wind

  25. Solar corona

  26. Solar prominences

  27. X-rays solar corona

  28. PhotosphericfieldsChromosphere u = u0+du

  29. Energyreleasethroughflares

  30. Coronalmassejections

  31. Solar wind particles

  32. Magneticfieldof Earth: Protection

  33. Effects on Spacecraft and Aircraft electronics I • A variety of effects from the particles: • Total dose • Lattice displacement damage • Single events upsets (SEE) • Noise in sensor • Spacecraft charging

  34. Effects on spacecraft and aircraft electronics II • Cosmic radiation: (protons, highly ion. Heavier nuclei); production of atmospheric secondaries (effects in aircraft systems and sea level electronics); SEEs, background noise • Solar particle events: increase of SEEs; significant enhancements in the radiation at supersonic aircraft altitudes. • Inner Radiation Belt: dose damage, noise and SEE • Outer Radiation Belt: energetic electrons; cummulative dose and dammage effects; deep dielecrtic charging (responsible for anomalies and losses); surface charging anomalies.

  35. Orbit and Perturbations • Temperature, composition and horizontal winds in the Earth‘s atmosphere at orbital altitudes above 120 km are all influenced by variations of solar and geomagnetic activity. • Atmospheric drag: F=C ½ rv^2A • Solar radiation force: F=C I/cS, S cross sectional area perpendicular to the direction of solar rays.

  36. Red: density increase by 20% during a magnetic storm. Emissions from the sun: UV, X; if in addition Magnetic activity is triggered at Earth, intense currents flowing through the upper Atmosphere and energy deposited by high speed particles increase the heating and expansion of the Atmosphere.

  37. Atmopsheric drag and lost objects in orbit

  38. SAM- Solar Activity Monitoring • Kanzelhöhe: H-Alpha Magnetograms Intensity at various wavelengths International network

  39. The Sun today, Nov. 29, 2007

  40. The Sun today, SOHO EIT, 171 LASCO

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