Observations of Sunspot Groups
with Solar Optical Telescope (SOT)SOT による黒点群の観測

Takako T. ISHII(石井 貴子)
Kwasan and Hida Observatories, Kyoto-U., JAPAN京都大学大学院 理学研究科 附属天文台

ishii@kwasan.kyoto-u.ac.jp

Subject:
Flare energy storage and release.
Question:
What is the common magnetic field configuration
to flare-productive active regions ?

Method:Study the evolution of active regions.
Birth, growth, and decay.
Photospheric vector-magnetic field (helicity).
Corona (XRT), chromosphere (H-alpha).

Previous works:
Schematic model of emerging flux bundles.
・Hida Domeless Solar Telescope (DST)e.g. Kurokawa 1987 Sol. Phys.
Ishii et al. 1998 ApJ, 2000 PASJ.

・NOAA 9026 (2000 June)
DST/ LaPalma H-alpha
TRACE white light, SOHO MDI
Kurokawa et al. 2002 ApJ.

Active Region NOAA 5395 (1989 March)

The most flare-productive region
during the last solar cycle 22

Twisted magnetic flux bundle model
Ishii et al. (1998) ApJ, 499, 898

Active Region NOAA 4201 (1983 June)
Observations by DST
have performed forten days running.

CB

High flare activity has
been found when(June 5-6) and where
the twisted magnetic
flux bundles (B, C)
emerged.
In region A,no flares have occurred.

AJune 2June 5June 6Ishii et al. (2000) PASJ, 52, 337

MDI magnetograms

NOAA 9026 (2000 June)
Twisted magnetic knot
( Kurokawa et al. 2002
ApJ 572, 598)

TRACE white lightOn going:
Active regions with X-class flares (about 30 ARs)

SOHO MDI full disk  daily evolution movies(1996 – 2001 done. 2002 in prep.)
East-limb  West-limb 11 days

Cadence:・Magnetograms
15 images / day ( one image / 90 min.)OK.

・Intensitygrams
4 images / day ( one image / 6 hours)
a little bit poor.

NOAA 9415 (2001 Apr.)

5 X-class flares(e.g. 2001-Apr-10 Asasi-flare)

600 arcsec

SOHO / MDImagnetograms

SOHO / MDI
intensitygrams

NOAA 9415
(Face-on movie)
gray scale: intensitygram
contour: magnetogramlevel: 500 Gauss
red: positive
blue: negative
20 degrees
in heliographic coordinate

SOHO / MDI Full disk
Longitudinal magnetogram
1 pixel = about 2 arcsec

Solar-B / SOT
Vector-magnetogramHigh resolution

NOAA 9236 (2000 Nov.)

TRACE White light
SOHO / MDI high-resolution
1 pixel = 0.5 arcsec

5 X-class flares

20 degrees
in heliographic coordinate

SOHO / MDIFull disk

contour: magnetic field (500 Gauss, red: positive, blue: negative)

Solar-B SOT
1 pixel = 0.08 arcsec
Field of View
(FOV)
⇒max:328’’×164’’

Full disk Sun

SOT FOVmaxNOAA 9415
2001-Apr-10
01:36 UT

X2 flare (Asai-flare)on Apr. 10, 2001.

NOAA 9077
2000-Jul-13
05:55 UT

X5 flare on July 14, 2000.

NOAA 9393
2001-Mar-29
00:00 UTThe largest region
during this cycle.
(X20 flare at west limb
on Apr. 02, 2001)

NOAA 9393
2001-Mar-30
00:00 UTThe largest region
during this cycle.
(X20 flare at west limb
on Apr. 02, 2001)

NOAA 9393
2001-Mar-30
00:00 UTMosaic

The largest region
during this cycle.
(X20 flare at west limb
on Apr. 02, 2001)

NOAA 9236
2000-Nov-23
11:12 UT

Fixed FOV
(19 hours)

NOAA 9236
2000-Nov-24
06:24 UT

Fixed FOV
(19 hours)

NOAA 9415
2001-Apr-10
01:36 UT
Rotation: 2km/s⇒ 10 arcsec / 1 hour

60 arcsec( 6 hours )Summary
FOV can cover whole active region.
We need fine pointing management (by OP).

NOAA 7978
1996-Jul-09
13:07 UT

X2.6 flare occurred in this region
on July 09, 1996.