1. Observation of Sigmoids with Solar-B
K.Hori
(Hiraiso Solar Observatory, CRL)

2. Sigmoids Classification
After Pevtsov 2002
Interlocking Loops
(Eruptive)
Multiple Loops
Single Loop
(Eruptive)
Inter-Region Sigmoid

3. Secrets of Sigmoids
　　- Magnetic topology (e.g., helicity, shear buildup)
Priest 1992; Titov et al．1993; Rust&Kumar 1996;
Demoulin et al. 1997; Amari et al. 2000….
- Connection with Eruptions
(e.g., missing mass deduced from dimming,
CMEs) Hudson&Webb 1997; Sterling&Hudson 1997
Canfield et al. 2000; Glover et al. 2000….
　- Formation and Evolution of Sigmoids
Sigmoid→Arcade/Cusp
Physical process involved in the formation of
sigmoids is still not clear.

4. Formation of Sigmoids By linkage of two initially
unconnected bipoles/ARs?
Martens & Zwaan 2001
Formation of
Sigmoids
By emerging below
the photosphere as a part
of a twisted flux tube?
Matsumoto et al. 1998;
Magara and Longcope 2001,…　　

5. Temperature Diagnosis of Interlocking Sigmoids
18-Oct-1994

6. Case1: AR Sigmoid 19-Oct-1994 Goes M3 SXT Al1+AlMg
Moore et al. 2001　
SXT Al1+AlMg
19:00:20-19:34:10
20:32:12-20:49:36
20:50:08-20:53:28
Flare
Early in the rise phase
(MK)

7. van Driel-Gesztelyi et al. 2000
Case2: AR Sigmoid
25-Oct-1994, C4.7
Manoharan et al.1996
van Driel-Gesztelyi et al. 2000　
SXT Al1+AlMg
09:47:09-09:50:21
10:00:39-10:03:55
11:28:55-11:32:11
Short
Loops
(MK)

8. Case3: Sigmoidal Filament
8-May-2000
B6.8
Yohkoh SXT Hα
17GHz (NoRH)
May 7
Hiraiso
10 km 5
May 8
Hida, FMT
04:35
04:00
04:26

9. 17GHz dark patch: Manifestation of low temperature regions
(Tb < 10 K ) 4
May 7
May 8
04:26:25
05:09:05
Heating has started.
The midpoint remained to be cold.

10. Sigmoid Evolution in Hα
04:58:00
05:10:00
05:36:00
Bifurcation and disappearance of the eastern half of the filament.
B6.8 Two-ribbon flare
08:09:31
SXT

11. Interlocking Sigmoids
Magnetic Structure of
Interlocking Sigmoids = + ? ?

13. Yohkoh SXT was the best observational
tool to reveal the secrets of Sigmoids
if.....
the observations were not interrupted so often by Yohkoh nights.
the SXR brightness of flare regions were not saturated →　Exposure time, temperature range
velocity and magnetic field maps could be obtained simultaneously with temperature and EM maps.
→XRT,SOT,EIS