Relationship between magnetic field evolution and major flare event on July 14, 2000

Beijing Astronomical Observatory, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China

Corresponding author: Y. Liu, lyu@sun10.bao.ac.cn

Received: 9 February 2001
Accepted: 11 April 2001

Abstract

On July 14, 2000 the active region NOAA 9077 produced one of the largest solar flares (3B/X5.7) seen in recent years associated with a violent halo coronal mass ejection (CME). It had a magnetic classification and the morphology of the sunspot group and magnetic field changed obviously every day. We present here the relationship between the large scale motions of the spots and the major flare on July 14, based on precise measurements of the proper motions. We find that: (1) The special magnetic morphology and quick, successive fragmentation caused the active region to be always in a high shear configuration; (2) There is a good spatial correspondence between the direction of the movement of one spotgroup and the place where the filament was cut off and activated; (3) The motion characteristics of the rapidly emerging flux system showed a good correlation between spot motions and the largest flares, suggesting that the initiation of the two-ribbon flare on July 14 was promoted by the successive emergence of the flux systems. The intensive major flare was always connected strongly with a newly emerging magnetic flux system (Kálmán 1997). This confirms that δ-configurations and dynamical processes are important in large flares.