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5th Alfvén Conference

5th Alfvén Conference. on “Plasma Interaction with Non-magnetized Planets/Moons and its Influence on Planetary Evolution”. www.ep.sci.hokudai.ac.jp/~alfven5. 4-8 October, 2010 Sapporo, Japan. Mars, Venus, The Moon, and Jovian/Saturnian satellites.

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5th Alfvén Conference

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  1. 5th Alfvén Conference on “Plasma Interaction with Non-magnetized Planets/Moons and its Influence on Planetary Evolution” www.ep.sci.hokudai.ac.jp/~alfven5 4-8 October, 2010 Sapporo, Japan Mars, Venus, The Moon, and Jovian/Saturnian satellites

  2. Reflected solar wind in the foreshock region: a Venus-Mars comparison by VEX and MEX M. Yamauchi1, Y. Futaana1, S. Barabash1, R. Lundin1, A. Fedorov2, C. Mazelle2, J.-A. Sauvaud2, J.D. Winningham4, R.A. Frahm4, T.L. Zhang3, W. Baumjohann3, E. Dubinin5, and M. Fraenz5. (1) IRF, Kiruna, Sweden, (2) CESR, Toulouse, France, (3) SwRI, San Antonio, USA, (4) OEAW, Graz, Austria, (5) MPS, Göttingen, Germany Europlanet 2009, TP3 (Tuesday 15/9/2009)

  3. Foreshock = full of accelerated ions

  4. Outline 1. Introduction = Earth's knowledge 2. Venus (similar to Earth) 3. Mars (Different from Venus/Earth) But it gives some hint on the acceleration process

  5. Earth’s case= since 1970’s B

  6. Earth: B (Oka et al., 2005) (Cao et al., 2008) * Moving upstream * Energized * Localized (by B) FAB V// V// SW SW cluster-3 cluster-1 V V

  7. Venus (Venus Express) No internal magnetic field. Planet is the same size as the Earth.  Smaller bow shock size than the Earth, yet MHD regime.

  8. VEX connected by B not connected , ∑ 3-min scan BS SW BS

  9. Venus ≈ Earth B B foreshock 2006-6-18 connected to BS = foreshock SW scan = -45°~+45°

  10. pitch angle distribution SW SW SW FAB in the SW frame FAB in the Venus frame SW

  11. Mars (Mars Express) No internal magnetic field. Planet is the smaller than the Earth.  The bow shock size is too small to treat with MHD.

  12. Mars = weak & complicated

  13. Detail of spectrogram (E=1~15 keV)  =4  =3  =2  =1  Mixture of accelerated ion (H+) components  =all

  14. B (N-direction) is estimated from MVM.

  15. Special features for Mars // beam at only close to BS, and many with the same V as ring (V0=0)  accelerated ions even at upstream (no velocity filter?) Energy is stepping for // direction To examine the acceleration history, we superposed 9 scans

  16. accel. gyrate. accel.

  17. Summary Venus Express / ASPERA-4 often observes nearly field-aligned beam-like H+ (FAB) in the foreshock region of Venus: * They travel away from QL bow shock of Venus, along IMF. * About 2~6 times energy of the SW H+ energy. They are similar to those at the terrestrial foreshock region. * Combination of two beams forming a pancake-like distribution: (a) field-aligned beam in the SW frame of reference, and (b) field-aligned beam in Venus frame of reference which gyrates in the SW frame. Mars Express / ASPERA-3 (same instrumentation as VEX) observed less intense but more complicated zoo of accelerated ions in the Martian foreshock region. The observation suggests the history of the acceleration. The finite gyroradii effect makes Mars a perfect laboratory.

  18. Mars case 2: 2005-6-3

  19. case 2

  20. Mars case 3: 2005-8-5

  21. case 3a

  22. case 3b

  23. Mars case 4: 2005-8-3

  24. case 4

  25. Venus ≈ Earth B B B B 2006-6-18 connected to BS 2008-10-28 connected to BS Beam = foreshock Sometimes no beam in foreshock

  26. Venus e- (top) & H+ (rest) at different angle , ∑ 3-min scan SW SW SW SW BS BS BS BS Scan=-45°~45°

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