1. KASI - 0 - Low atmospheric reconnections associated with an eruptive flare Yong-Jae Moon(1), Jongchul Chae(2), Young-Deuk Park(1) 1: Korea Astronomy and Space Science Institute 2: Seoul National University

2. KASI - 1 - Outline We present an observational study of the filament-flare-CME event on Nov. 24, 2000 with the following topics: 1. Preflare Activity 1. Preflare Activity 2. Preflare Activity and Canceling Magnetic Feature (CMF) 2. Preflare Activity and Canceling Magnetic Feature (CMF) 3. Pre-flare Activity and Filament Eruption 3. Pre-flare Activity and Filament Eruption 4. Filament Kinematics and CME 4. Filament Kinematics and CME

3. KASI - 2 - Advantages of Present Study  Near simultaneous observation of MDI, TRACE 1600, BBSO H-alpha centerline and bluewing : 1-min time cadence and 1’’ spatial resolution  Initial filament kinematics is well examined (10-160km/s for the first twenty minutes) (10-160km/s for the first twenty minutes)  We study the relationship among preflare brightenings, canceling magnetic features, and initial filament kinematics

4. KASI - 3 - 1. 1.Preflare Activity SOHO/MDI H-a center H-a blue TRACE 1600

5. KASI - 4 -  Two brightenings (B1 and B2) are just near one footpoint of the filament and cospatial with two CMFs SOHO/MDI H-a center TRACE 1600

6. KASI - 5 - Small-scale Eruptive Events  Recurrent small-scale UV eruptive events near the one footpoint of the filament near the eruption time. 1) Projected speed : 140 km/s 1) Projected speed : 140 km/s 2) It may be a result of low atmosphere reconnection. 2) It may be a result of low atmosphere reconnection. TRACE 1600

7. KASI - 6 - TRACE EUV loop eruption Sturruck et al. (2001)

8. KASI - 7 - 2. Canceling Magnetic Features  Sonic filter : 4km/s  Flux variations of two CMFs 1) A tendency : first increase and then decrease 1) A tendency : first increase and then decrease : imply “ First : imply “ First emergence and then reconnection” emergence and then reconnection” 2) Brightenings (B1,B2) occurred in the flux decrease phase 2) Brightenings (B1,B2) occurred in the flux decrease phase

9. KASI - 8 - 3. Preflare Activity and Eruption  From BBSO H-alpha data, we derived ejection speeds  Eruption started at 21:30 UT with 10km/s, which is 10-20 minutes earlier than the flare onset  Pre-flare brightening (near 21:32 UT) is coincident with the eruption time.

10. KASI - 9 - 4. Filament Kinematics and CME  The maximum acceleration occurs near the peak time of the the flare.  Initial exponential growth : may be explained by flux injection (Chen) or mass drainage (Low) instabilities(Forbes)

11. KASI - 10 - EIT Running Difference Image  A direction of the EIT wave feature seen in the last image : consistent with the direction of a LASCO CME seen at 22:06

12. KASI - 11 - LASCO Running Difference Image

13. KASI - 12 - Summary  There are noticeable preflare brightenings which are located near one footpoint of the filament.  They are most evident in Trace UV and H-alpha images and are cospatial with CMFs.  The CMFs show a tendency of “flux increase and then decrease” and they seem to be triggered by flux emergence and/or motions.  Preflare activity, CMFs, and UV eruptive events may imply low-atmosphere reconnections.  One major pre-flare brightening responsible for the flare precursor is coincident with the eruption time.  The above activities may play important role in the onset of the filament eruption.

14. KASI - 13 - Future Works  From a statistical study of filament-flare-CME events, we will address several questions: 1. What is preflare activity ? 1. What is preflare activity ? 2. Is CMF responsible for flare precursor ? 2. Is CMF responsible for flare precursor ? 3. Is statistically significant CMF frequency near eruption time ? 3. Is statistically significant CMF frequency near eruption time ? 4. Is there any difference between eruptive and non- eruptive events ? 4. Is there any difference between eruptive and non- eruptive events ? 5. What is the relationship among preflare activity, CMFs, flare precursor, and filament eruption ? 5. What is the relationship among preflare activity, CMFs, flare precursor, and filament eruption ? 6. What is the implication on the CME onset time ? 6. What is the implication on the CME onset time ? Solar-B and SDO may give more definite answers. Solar-B and SDO may give more definite answers.

15. 19:46 1999 Jan 16 M1.2 Yohkoh Soft X-rayTRACE 1600 Å Foot point Brightening Sigmoid and eruption Flaring time Flaring time 19:50 ~ 20:02 Pre-flare time Pre-flare time19:46