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Low atmospheric reconnections associated with an eruptive flare

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. Outline.

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Low atmospheric reconnections associated with an eruptive flare

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  1. 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 KASI

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

  3. 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) • We study the relationship among preflare brightenings, canceling magnetic features, and initial filament kinematics KASI

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

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

  6. 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 2) It may be a result of low atmosphere reconnection. TRACE 1600 KASI

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

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

  9. 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. KASI

  10. 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) KASI

  11. 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 KASI

  12. LASCO Running Difference Image KASI

  13. 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. KASI

  14. Future Works • From a statistical study of filament-flare-CME events, we will address several questions: 1. What is preflare activity ? 2. Is CMF responsible for flare precursor ? 3. Is statistically significant CMF frequencynear eruption time ? 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 ? 6. What is the implication on the CME onset time ? Solar-B and SDO may give more definite answers. KASI

  15. 19:46 1999 Jan 16 M1.2 Foot point Brightening Sigmoid and eruption Yohkoh Soft X-ray TRACE 1600 Å

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