Observation of Sigmoids with Solar-B

K.Hori (Hiraiso Solar Observatory, CRL)

Sigmoids ClassificationAfter Pevtsov 2002

Multiple LoopsInterlocking Loops (Eruptive)

(Eruptive)Inter-Region Sigmoid

Single Loop

Physical process involved in the formation of sigmoids is still not clear.

Secrets of Sigmoids

Sigmoid→Arcade/Cusp

　　 - 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

By linkage of two initially unconnected bipoles/ARs?

Martens & Zwaan 2001

Matsumoto et al. 1998; Magara and Longcope 2001,… 　　

By emerging below the photosphere as a part of a twisted flux tube?

Formation of Sigmoids

Temperature Diagnosis of Interlocking Sigmoids

18-Oct-1994

Case1: AR Sigmoid

19:00:20-19:34:10 20:32:12-20:49:36 20:50:08-20:53:28

(MK)

SXT Al1+AlMg

19-Oct-1994Goes M3

Moore et al.

2001 　

Flare

Early in the rise phase

09:47:09-09:50:21 10:00:39-10:03:55 11:28:55-11:32:11

ShortLoops

Case2: AR Sigmoid Manoharan et al.1996

van Driel-Gesztelyi et al. 2000 　

SXT Al1+AlMg

25-Oct-1994, C4.7

(MK)

Hα 17GHz (NoRH)Yohkoh SXT

10 km5

May 8

04:35

Hida, FMT

04:2604:00

May 7 Hiraiso

Case3: Sigmoidal Filament 8-May-2000

B6.8

4

17GHz dark patch: Manifestation of low temperature regions (Tb < 10 K )

Heating has started.

04:26:25 05:09:05

May 7 May 8

The midpoint remained to be cold.

1. Bifurcation and disappearance of the eastern half of the filament.

2. B6.8 Two-ribbon flare

Sigmoid Evolution in Hα

SXT08:09:31

04:58:00 05:10:00

05:36:00

+=

?

?

Magnetic Structure of Interlocking Sigmoids

Moore et al. 2001

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.

Yohkoh SXT was the best observational tool to reveal the secrets of Sigmoids

if.....

→XRT,SOT,EIS