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Solar-B Science Objectives - Overview of the Mission -

Solar-B Science Objectives - Overview of the Mission -. Kazunari Shibata (Kyoto Univ.). Science Objectives of Solar-B Mission. Kosugi (1999) coronal heating coronal dynamics and structure elementary processes such as reconnection. chromospheric heating, spicules, ….

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Solar-B Science Objectives - Overview of the Mission -

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  1. Solar-B Science Objectives- Overview of the Mission - Kazunari Shibata (Kyoto Univ.)

  2. Science Objectives of Solar-B Mission Kosugi (1999) • coronal heating • coronal dynamics and structure • elementary processes such as reconnection chromospheric heating, spicules, … jets, prominence, CME, solar wind, waves/shocks,… reconnection jet, inflow, slow/fast shocks,… - emerging flux and dynamo flux tubes, sunspots, convection, …

  3. These Objectives are also important for astrophysics and space weather • To explore solar MHD as a laboratory of astrophysical MHD • To explore solar activity as a basis of space weather research

  4. Plan of this talk • Introduction – Main Instruments • Main Objectives • Coronal and Chromospheric Heating Nanoflares, Alfven Waves, Spicules • Coronal Dynamics and Structure Jets, CMEs, Coronal Waves/Shocks • Reconnection • Emerging Flux • Summary

  5. Solar-B Mission • Solar Optical Telescope (SOT) • X-Ray Telescope (XRT) • EUV Imaging Spectrometer (EIS) • Launch Date: 2005 J-fiscal year • Mission Lifetime: > 3 years • Orbit: Polar, Sun Synchronous

  6. Solar Optical Telescope (SOT) • 50 cm Aplanatic Gregorian – Japan • Focal Plane Package – US(LMATC) (Filtergram+Spectro-polarimeter) • => 0.2 arsec resolution; 380-700 km vector magnetic field measurements

  7. X-Ray Telescope (XRT) • Grazing-Incidence Optics – US(SAO) • CCD Camera – Japan • => 1 arcsec resolution; 1 – 30 MK

  8. EUV Imaging Spectrometer (EIS) • 15 cm Offset Parabolic Mirror, Slit/Slot & Multilayer Grating – US (NRL, GSFC) • Camera – UK(MSSL,RAL,Birmingham) • Controller – Japan • 20 km/s nonthermal motion • 2 arcsec spatial resolution • Temperature coverage 0.1 – 20 MK

  9. 太陽活動の１１年周期 黒点数

  10. Yohkoh HXT Flares in 1991-1998 2005 - 2007

  11. 2005 Nov Predicted Solar Corona in 2005-2007 2007Sep(minimum) • Sep (minimum) • 2007 Sep ? 1994 Nov 2005 Nov ?

  12. Coronal HeatingAlfven wave vs Nanoflare • Alfven Wave heating • Nanoflare heating

  13. Nanoflare Heating ? • Shimizu (1995) Ph. D. Thesis active region corona is filled withmicroflare/nanoflare　 　　　　 ＝＞　nanoflare heating ?　　　 • Kano (1997) Ph. D. Thesis loop top heating ? • Priest et al. (1998) nanoflare heating ?

  14. Microflare/Nanoflare Occurrence Frequency α＝1.6-1.7 ＜２ Shimizu, Shimojo, Aschwanden, …. => insufficient for coronal heating α＞２ Krucker & Benz

  15. Alfven Wave Heating ? • Yashiro (2000) Ph. D. Thesis Ｌｘ（active region）　 ∝ 　Ｂ＾１．０７　　　 　Ｆ　 ∝　　Ｂ ＝＞　　Alfven wave heating ?

  16. Alfven wave theory of Spiculesand Coronal Heating(Hollweg et al. 1982, Kudoh-Shibata 1999) Hα (Hida DST)

  17. Alfven wave model of spicules:numerical simulation (Kudoh-Shibata 1999)

  18. Energy Flux Carried by Alfven Waves into Corona (Saitoh, Kudoh, Shibata 2001)

  19. Nonthermal Line Width(Kudoh & Shibata 1999)

  20. Coronal Heating(Kudoh &Shibata 1999)

  21. Question on Coronal Heating • What is the true occurrence frequency of nanoflare ? • What is the heating rate and its dependence upon magnetic field ? • What is the energy flux carried by Alfven waves into the corona ? • What is the origin of Alfven waves ? Photospheric turbulence or reconnection ?

  22. Coronal Dynamics and Structure: X-ray Jet Yokoyama & Shibata (1995)

  23. CDS spinning jet (Pike&Mason) Zoo of Solar Jets • H alpha jets (surges) • EUV macrospicules • EIT jets • LASCO jets Cosmic jet (HST) H alpha spinning jet (Kurokawa) EIT-LASCO jet (Wang, Y. M.)

  24. Polar plume Evaporation flow produced by reconnection heating ? (Wang, Y.M. 1999)

  25. Moreton Wave(Hα：Hida FMT, Eto et al. 2001) Moreton wave = Fast mode MHD shock (Uchida 1968)

  26. Wave front of Moreton wave Propagation speed ~ 720km/s 5：55

  27. 5:40 - 5:31 5:58 - 5:40 ② ① 6:14 - 5:58 6:31 - 6:14 ③ ④

  28. Moreton wave and EIT wave EIT wave EIT wave (Thompson et al. 1998) Moreton wave

  29. Photospheric flare wave(SOHO/MDI, Kosovichev)

  30. Question on Coronal Dynamics and Structure (Jets and Waves) • What is the true velocity of X-ray jets ? • What is the acceleration mechanism of X-ray jets ? ( => Shimojo’s talk) • What is the relation to coronal heating and acceleration of high speed solar wind ? • What is EIT wave ? • What is the origin of Moreton wave ?

  31. Reconnection • Yohkoh found plenty of evidence of reconnection in flares. • But we have not seen reconnection jet and inflow in SXT images. (but see Yokoyama et al. 2000 ApJ Let.)

  32. Reconnection Rate of a Cusp-Shaped Flare on May 12, 1997(Isobe et al.　=> poster) Reconnection rate is high even in a very late decay phase V_inflow/V_A= 0.001 – 0.01

  33. Question on Reconnection • Are there really high speed reconnection jets with 1000 km/s ? • What is the reconnection rate (inflow speed) in solar flares, jets, and coronal mass ejections ? • What determines the reconnection rate ? => Yokoyama’s talk

  34. Emerging Flux Region Emerging Flux Region (EFR) is important for (1) Dynamic Phenomena (2) Dynamo (3) Coronal Heating

  35. TRACE Observation of Emerging Flux Wavelength ～ 171 Ａ Time cadence～ 1 min Spatial Resolution ～ 2 arcsec Dark : Chromosphere Bright : Corona

  36. Comparison with SXT (Yashiro-Shibata) TRACE SXT

  37. Emergence of twisted flux tube - most fundamental driver of solar activity ? - (Matsumoto et al. 1998)

  38. Question on Emerging Flux • How and when are kG intense flux tubes created in emerging flux ? • How and why are twisted emeging flux tubes generated ? • Will we observe flare-like explosive reconnection (with jets and shocks) in photospheric reconnection associated with emerging flux ?

  39. Summary • More, smaller, and fasterjets, plasmoids, waves, and shocks would be found by Solar-B. • High time cadence velocity field observations (with EIS and SOT) with good coordination with XRT is extremely important.

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