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Ulysses: Cosmic rays in 4 Dimensions

Mathematisch-Naturwissenschaftliche Fakultät. Ulysses: Cosmic rays in 4 Dimensions. Bernd Heber on behalf of the KET team Rome, 12.05.2009. Mathematisch-Naturwissenschaftliche Fakultät. Outline. The Sun and the Heliosphere The Ulysses mission Energetic Particles (in the heliosphere)

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Ulysses: Cosmic rays in 4 Dimensions

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  1. Mathematisch-Naturwissenschaftliche Fakultät Ulysses: Cosmic rays in 4 Dimensions Bernd Heber on behalf of the KET team Rome, 12.05.2009

  2. Mathematisch-Naturwissenschaftliche Fakultät Outline • The Sun and the Heliosphere • The Ulysses mission • Energetic Particles (in the heliosphere) • Importance of the polar regions (Ulysses results) • Summary and Outlook

  3. Mathematisch-Naturwissenschaftliche Fakultät The Sun and the Heliosphere

  4. Mathematisch-Naturwissenschaftliche Fakultät • The Atmosphere of the Sun extends into interstellar space • Forming the heliosphere • Termination shock (90 AU) • Heliopause (180 AU) • Bow shock (350 AU)

  5. Mathematisch-Naturwissenschaftliche Fakultät What is Ulysses? Ulysses is ... • A collaborative project between ESA and NASA • The only space-probe in a solar-polar orbit • A mission to explore the heliosphere as an integrated system and conduct investigations of the Sun, the local interstellar medium, and the universe History ... • A mission that eventually became Ulysses was proposed as early as 1959 (2 years after Sputnik!) • The project started officially in 1977, with a launch foreseen in 1983 • After many delays, Ulysses was finally launched on 6 October 1990, from the space shuttle Discovery

  6. Mathematisch-Naturwissenschaftliche Fakultät Exploration of the polar regions by Ulysses

  7. Mathematisch-Naturwissenschaftliche Fakultät McComas et al., GRL, 2002

  8. Propagation Photons: direct connection Charged particles: Reflection in galactic magnetic fields e+e- g Modulation in the heliosphere

  9. Mathematisch-Naturwissenschaftliche Fakultät Space probes in the heliosphere • 1 AU: IMP, ACE, Sampex, SOHO, STEREO, neutron monitors, and PAMELA • Ulysses: (1.3<r< 5AU 80,2 < θ < 80,2) • Voyager 1 (r >100 AU) • Voyager 2 (r>80 AU

  10. Mathematisch-Naturwissenschaftliche Fakultät Observations of galactic cosmic rays in the heliosphere: Solar modulation at neutron monitor energies • Variations with the 11-year solar magnetic cycle • The amplitude depend on particle rigidity

  11. Mathematisch-Naturwissenschaftliche Fakultät Observations of galactic cosmic rays in the heliosphere: Charge sign dependence • Shape and amplitude depend on particle charge sign • Solar modulation cycle is the 22-year Hale cycle

  12. Mathematisch-Naturwissenschaftliche Fakultät Observations of galactic cosmic rays in the heliosphere Latitudinal Gradient Radial Gradient

  13. Mathematisch-Naturwissenschaftliche Fakultät Exploration of the polar regions by Ulysses

  14. Mathematisch-Naturwissenschaftliche Fakultät Kiel Electron Telescope on board Ulysses Relativistic Electrons: ~10 Minutes 50 MeV Protons: 30-80 Minutes

  15. Mathematisch-Naturwissenschaftliche Fakultät Kiel Electron Telescope on board Ulysses Relativistic Electrons: ~10 Minutes 50 MeV Protons: 30-80 Minutes

  16. Ulysses COSPIN/KET observations Three fast latitde scans: 1994/1995: Solar minimum; A>0-magnetic epoch 2000/2001: Solar maximum 2007/2008: : Solar minimum; A<0-magnetic epoch

  17. Mathematisch-Naturwissenschaftliche Fakultät The heliosphere and the heliospheric magnetic field • Expectation in the 1970’s for galactic cosmic ray intensities over the poles of the Sun

  18. Mathematisch-Naturwissenschaftliche Fakultät Cosmic ray distribution at solar minimum (A > 0) The LIS can not be measured over the poles of the Sun Expectation before Ulysses: Ulysses will measure the LIS over the poles of the Sun

  19. Mathematisch-Naturwissenschaftliche Fakultät Electron gradients at solar minimum (A > 0) Electrons show no latitudinal gradient

  20. Mathematisch-Naturwissenschaftliche Fakultät The heliosphere and the heliospheric magnetic field • Drift pattern in the Parker like heliospheric magnetic field

  21. Ulysses COSPIN/KET observations Three fast latitde scans: 1994/1995: Solar minimum; A>0-magnetic epoch 2000/2001: Solar maximum 2007/2008: : Solar minimum; A<0-magnetic epoch

  22. Mathematisch-Naturwissenschaftliche Fakultät Electron gradients during the A<0-magnetic epoch

  23. Mathematisch-Naturwissenschaftliche Fakultät The fourth dimension: The solar cycle

  24. Mathematisch-Naturwissenschaftliche Fakultät Variations with the 22-year solar magnetic cycle

  25. Mathematisch-Naturwissenschaftliche Fakultät Tilt [degree]

  26. Mathematisch-Naturwissenschaftliche Fakultät Consequences for the recent solar minimum The galactic cosmic ray intensity should increase by more than 20% when the tilt angle drops below 10o

  27. Mathematisch-Naturwissenschaftliche Fakultät Summary • The galactic cosmic ray intensity is altered by solar modulation • Latitudinal gradients of protons and electrons in the inner heliosphere are smaller than expected and even vanishing for the A>0-solar magnetic epoch. • The opposite is true for the A<0-solar magnetic epoch. • Current solar minimum remarkable because tilt and sunspot number out of phase • Simultaneous electron and proton measurements allow to predict the real solar minimum flux.

  28. Mathematisch-Naturwissenschaftliche Fakultät No gradient → ratio = 1 Latitudinal gradient → ratio depend on latitude (He) GCR-distribution expected to be symmetric around the heliospheric equator The galactic cosmic ray distribution shows a North-South Asymmetry

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