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 of active 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. Method Emerging magnetic flux tube Bipolar pair of sunspots
photosphere
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
bundles is 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. 20 degrees in heliographic coordinate
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
SOHO / MDI Full disk
(magnetogram, intensitygram)
1 pixel = about 2 arcsec
TRACE white light
MDI high resolution
1 pixel = 0.5 arcsec

8. NOAA 9236 (Face-on movie) Solar-B / SOT Vector-magnetogram
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 days
・Magnetograms
15 images / day ( one image / 90 min.)
OK.
・Intensitygrams
4 images / day ( one image / 6 hours)
a little bit poor.

12. Attention Trigger of flares: Magnetic fields ・Magnetic shear
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°)