Pre-flare activity of M1.2 flare 김수진 1,2, 문용재 1, 김연한 1, 박영득 1, 김갑성 2 1. Korea Astronomy and Space Science Institute 2. Kyung Hee University

Contents  Introduction  Data  Result  Summary  Future work

Pre-flare Pre-flare Introduction  Enhancement before impulsive phase  Well defined at the soft X-ray wavelength X-ray wavelength  Trigger main flare and solar eruption?  Independent energy release  magnetic reconnection ?

Relationship with solar activity   Simnett, Harrison (1984) CME onset time ≈ pre-flare time ≈ pre-flare time  Ohyama (1997) 1993 C9.7 Pre-flare heating (11 ± 4MK) Pre-flare heating (11 ± 4MK) ≈> plasma ejecta ≈> plasma ejecta  Moon et al. (2004) 2000 X1.8  pre-flare brightenings just before the eruption near the footpoint the eruption near the footpoint of the filament of the filament Introduction

Research of pre-flare using various observations - Multi-wavelength brightenings & reconnection - Multi-wavelength brightenings & reconnection : Harry Warren(1999), Zhang Heng(2000), : Harry Warren(1999), Zhang Heng(2000), S.A. Matthews(2003) so on. S.A. Matthews(2003) so on.  They can’t show loop structure like reconnection  We report brightening and loop reconnection associated with pre-flare activity using high resolution data. Introduction

Data (1999/1/16 M1.2)  Yohkoh SXT ٥ 0.25 ~ 4.0kev (3–60Å) filter Thin Aluminum ٥ 0.25 ~ 4.0kev (3–60Å) filter Thin Aluminum ٥ Quiet Mode (QT) - Time R ~ 3min ٥ Quiet Mode (QT) - Time R ~ 3min ٥ Partial Frame Image (PFI) - pixel R : 5″, FOV : 5′ ٥ Partial Frame Image (PFI) - pixel R : 5″, FOV : 5′  Yohkoh BCS (Bragg Crystal Spectrometer) : S XV ~5 Å  GOES 8 X-ray flux curve : 0.5–4.0Å, 1.0–8.0Å  TRACE UV 1600Å : Time R = 30s, pixel R = 0.5″  BBSO Magnetogram

Results  Flaring time 19:50 ~ 20:02  Pre-flare time 19:46  AR 8440( E31N20 ) Pre-flare 19:46 1.0~8.0A 0.5~4.0A

Temperature (GOES) Pre-flare ~ 6MK Flare ~ 16MK

Light curves GOES : BCS/Yohkoh Full Sun SXT (3min) : TRACE 1600 Å (30s) Pre-flaring region BCS GOES flux TRACE SXT

Size ~ 20 arcsec Yohkoh Soft X-ray ″ Pixel R = 10 ″ TRACE 1600 Å ″ Pixel R = 0.5 ″ Foot point Brightening Sigmoid and eruption X-ray & UV images

Magnetogram (BBSO)

X-ray & UV images

19:39:29 UT19:40:0419:43:28 19:45:48 19:46:24 19:46:59 a a b b a a b a b a b b a = -b = +12 3

Tether cutting Moore & Sterling 2001 loop structure Van Ballegooijen 1989

Summary  At pre-flare time, there are brightenings in GOES X-ray, SXT partial frames, BCS and TRACE UV 1600A.  TRACE UV images show small-scale sigmoid loops which are co-spatial with SXT brightening foot point on the polarity inversion line.  There was the interaction between sheared loops and then large-sized rising loops were formed.  The evolution of these loops is similar to Moore(1999), Van Balliegooijen (1989) Model.  Our studies imply that the small-scale pre-flare activity be due to magnetic reconnection.