1. Multiwavelength Study of Magnetic Reconnection Associated with Sigmoid Eruption Chang Liu BBSO/NJIT 20080401

2. BBSO/NJIT 2/14 I.A brief summary of 2005 May 13 M8 event II.Ongoing Study: A successive flaring event (X1.5 + X1.4 + M9) on 2005 September 13 with an emphasis on a high speed plasma flow between flaring regions Outline

3. BBSO/NJIT 3/14 Three Trigger Mechanism for Large, Fast CME Moore & Sterling (2006)

4. BBSO/NJIT 4/14 I. 2005 May 13 M8 Flare: A Comprehensive View 1 st evidences of internal tether-cutting as trigger; Ribbon-like HXRs; Spatial SHS behavior of HXR; Anticorrelation of vB field and HXR spectral index (ApJ 658-L127; 664-L127; 669-1372; 672-L69)

5. BBSO/NJIT 5/14 Future Effort Can NLFF extrapolation model the preflare sigmoid and postflare arcade fields, towards a better understanding of tether-cutting reconnection?

6. BBSO/NJIT 6/14 II. Successive Flaring on 2005 September 13 βγδ Partial sigmoid eruption: only eastern part of the overall sigmoid is involved Long-duration event (~100 min) with multiple SXR peaks Disk event in AR 10808

7. BBSO/NJIT 7/14 X1.5 X1.4 M9 weak type II burst associated with filament eruption Event temporal evolution III Positively drifting features I and II, signifying downward propagating plasmoid broadband type IIId burst signifies the beginning of impulsive phase of X1.4 OVSA GBSRBS X1.5 + X1.4 + M9 Triple Flares

8. BBSO/NJIT 8/14 High Speed Plasma Flows: from SE towards NW X1.4 flare at the main δ spot speed as high as ~350 km/s, co-temporal with starting of nonthermal peaks

9. BBSO/NJIT 9/14 The flows are toward a coronal HXR source over the compact X1.4 flare at δ spot Hα kernels Looptop HXR source footpoint HXR source Hα + HXR (blue wing; 25-50 keV) Flow path The looptop HXR source is present for ~10 minutes from ~19:54 UT, during which the flows are seen.

10. BBSO/NJIT 10/14 One possible scenario, but… Shibata et al. 1995

11. BBSO/NJIT 11/14 (cont.) Flows in Hα: brighten at the northern end, and possibly trigger the following M8 flare identified as running kernels A & B A BBB A B A B

12. BBSO/NJIT 12/14 M9 Flare Hα + HXR (blue wing; 25-50 keV) BA

13. BBSO/NJIT 13/14 Another speculation of Flaring Scenario M9X1.4

14. BBSO/NJIT 14/14 Future Effort 1.NLFF extrapolation to aid identifying flux systems that lead to these three successive flares. Hope it will help to pin down the nature of the flows (e.g, along field line or not). 2.OVSA radio imaging to further help map out the energy release steps of the events