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Studies on Twisted Magnetic Flux Bundles by Solar Optical Telescope (SOT)

Studies on Twisted Magnetic Flux Bundles by Solar Optical Telescope (SOT). Takako T. ISHII. Kwasan Observatory, Kyoto-U. Contents; ・ Our previous studies ・ Advantage of Solar-B. Our previous studies We have studied what is the key process to trigger

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Studies on Twisted Magnetic Flux Bundles by Solar Optical Telescope (SOT)

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  1. Studies on Twisted Magnetic Flux Bundles by Solar Optical Telescope (SOT) Takako T. ISHII Kwasan Observatory, Kyoto-U.

  2. Contents; ・Our previous studies ・Advantage of Solar-B

  3. Our previous studies We have studied what is the key process to trigger the major solar flares using observational data of the evolution ofactive regions. Key question: What is the common magnetic field configuration among flare-productive active regions ? We have constructed schematic models of emerging magnetic flux bundles based on sunspot proper motions.

  4. Bipolar pair of sunspots photosphere photosphere Method Emerging magnetic flux tube proper motion proper motion Photosphere Chromosphere (H-alpha center)

  5. Data analysis ・Domeless Solar Telescope (DST) at Hida Observatory, Kyoto-U. 　⇒ H-alpha images by Lyot filter ・TRACE ⇒ White light images and EUV images ・SOHO / MDI 　⇒ Magnetograms and Intensitygrams Evolution of active regions (pair identification, sunspot proper motion) Flare activity (energy storage, trigger)

  6. For several active regions, we found that the emergence of twisted magnetic flux bundlesis the key to high productivity of major flares. Ishii et al. (2000) PASJ, 52, 337 ・NOAA 4201 (1983 June) Ishii et al. 2000 ・NOAA 5395 (1989 Mar.) Ishii et al. 1998 ・NOAA 9026 (2000 June) Kurokawa et al. 2002 ・NOAA 9236 (2000 Nov.) Ishii et al. 2002

  7. TRACE white light MDIhigh resolution 1 pixel = 0.5 arcsec SOHO / MDI Full disk (magnetogram, intensitygram) 1 pixel = about 2 arcsec 200,000 km NOAA 9236 (Face-on movie) gray scale: intensitygram contour: magnetogram level: 500 Gauss red: positive blue: negative 20 degrees in heliographic coordinate

  8. NOAA 9236 (Face-on movie) gray scale: white light contour: magnetogram level: 500 Gauss red: positive blue: negative 100 arcsec (70,000 km) TRACE white light MDI high resolution (Longitudinal magnetogram) Resolution : 1.0 arcsec Solar-B / SOT Vector-magnetogram Resolution: 0.2 arcsec

  9. SOT Field of View 1 pixel = 0.08 arcsec Field of View (FOV) ⇒max: 328’’×164’’ ～ 4 K×2 K CCD SOT FOVmax Full disk Sun

  10. NOAA 9236 2000-Nov-24 06:24 UT Full disk Sun

  11. Cadence <Example> SOHO MDI full disk  daily evolution East-limb  West-limb 11 days E 45 deg.  W 45 deg. 7 days ・Magnetograms 15 images / day ( one image / 90 min.) OK. ・Intensitygrams 4 images / day ( one image / 6 hours) a little bit poor.

  12. 200,000 km Attention Trigger of flares: Magnetic fields ・Magnetic shear development ・Helicity injection Sunspots ・Rotational motion of sunspots (vortex-like motions of satellite spots, penetration into opposite polarity region, rotation of magnetic neutral line) Kurokawa et al. (2002) ApJ, 572, 598 NOAA 9026

  13. Summary Subject: Flare energy storage and triggering process. Twists of magnetic flux tubes. Wavelength: White light & Vector magnetogram Field of View: SOT Max (328’’×164’’) Cadence: at least 15 images / day (1 image / 90min.) Duration: at least One week ( E45°～ W45°)

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