Presentation on theme: "RAPID CHANGES OF SUNSPOT STRUCTURE ASSOCIATED WITH SEVEN MAJOR FLARES C. Liu, N. Deng, J. Qiu, Y. Liu †, D. Falconer,P. R. Goode, C. Denker, H. Wang Center."— Presentation transcript:
RAPID CHANGES OF SUNSPOT STRUCTURE ASSOCIATED WITH SEVEN MAJOR FLARES C. Liu, N. Deng, J. Qiu, Y. Liu †, D. Falconer,P. R. Goode, C. Denker, H. Wang Center for Solar-Terrestrial Research, NJIT † Kwasan and Hida Observatories, Kyoto University Short report at Kwasan and Hida Obs. 2004/11/01
2 ABSTRACT By studying the change in TRACE white-light images, we find penumbral segments decayed rapidly and permanently right after seven major flares. Meanwhile, we observe central region (umbra/penumbra) enhancement near the magnetic neutral lines. The locus of penumbral decay is related to flare emission, either RHESSI HXR kernels or TRACE ribbon. MDI magnetogram and TRACE 195/171Å data are used to study the change of photospheric magnetic fields and coronal environment. We propose a possible explanation that magnetic fields change from a highly inclined to a more vertical configuration after the flares. We present more events exhibiting penumbra decay and we speculate that, this might be a universal phenomena associated with δ -sunspots.
3 Date Start (UT) Peak (UT) AR NumberSize Location (deg) 10/28/0309:5111:100486X17.S18E20 10/29/0320:3720:490486X10.S15W02 11/02/0317:0317:250486X8.3S14W56 06/06/0014:5815:259026X2.3N33E25 04/06/0119:1019:219415X5.6S20E31 04/09/0115:2015:349415M7.9S21W04 08/25/0116:2316:459591X5.3S17E34 Penumbra Decaying Events All these flares are originated from δ-sunspots
4 X10 flare on 10/29/03 D1 & D2: penumbra decaying areas, both associated with HXR kernels E1: central darkening area
5 Mean intensity increase indicates feature decaying; intensity decrease indicates darkening. After the X10 flare, intensities change rapidly and permanently. The associated photospheric longitudinal magnetic fields also exhibit rapid changes closely related to the flare.
6 MEES/IVM WL, B Z, AND B T MAPS It shows more clearly that the transverse fields associated with the two penumbra decaying areas (D1&D2) dropped after the flare, while enhanced at the central darkening region (E1). D1 D2 E1
8 TRACE 195Å IMAGES By comparing the change shown in the coronal images, it is obvious that new strong loops formed within the δ-sunspot region (red box) after the flare due to the magnetic reconnection.
9 X17 FLARE ON 10/28/03 D5 & D6: penumbra decaying areas, both associated with trace 1600å ribbons E3: central darkening area
10 TRACE 195Å IMAGES SUNSPOTS NOT CONNECTED CONNECTED
11 X8.3 FLARE ON 11/02/03 D3 & D4: Penumbra decaying areas, both associated with HXR kernels E2: central darkening area
12 TRACE 195Å IMAGES SUNSPOTS NOT CONNECTED CONNECTED
13 MORE EVENTS #1: 08/25/01 16:45 UT X5.3 FLARE D1: -20G D2: -36G E: +113G
14 MORE EVENTS #2: 04/06/01 19:21 UT X5.6 FLARE D1 D2 E
15 MORE EVENTS #3: 04/09/01 15:34 UT M7.9 FLARE D1 D2 E
16 MORE EVENTS #4: 06/06/00 15:25 UT X2.3 FLARE D2 D1 E
17 SUMMARY 1. All the events shown are two-ribbon flares and are associated with cmes 2. Two or more penumbra decaying areas are found which lie in the outer δ-sunspot structure 3. The central sunspot region (umbra or penumbra area) become darkened after the flare (DBD mode; D-dark, B-bright) 4. The two sunspots which constitute the δ-sunspot become connected after the flare 5. The observed intensity changes are permanent, not transient 6. The locus of penumbra decay is related to flare emission We propose a simple reconnection model for δ-sunspot which can explain both the penumbra decay and central area darkening
18 Possible reconnection scenario of δ-sunspot The penumbra fields change from a highly inclined to a more vertical configuration after the flare, and the two sunspots become connected penumbra decays and center darkens umbral fields penumbral fields