KASI 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 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

KASI 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

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

KASI  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

KASI 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

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

KASI 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

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

KASI 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 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 LASCO Running Difference Image

KASI 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 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.

19: 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