EDP Sciences
Free access
Volume 485, Number 2, July II 2008
Page(s) L13 - L16
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:200809813
Published online 27 May 2008

A&A 485, L13-L16 (2008)
DOI: 10.1051/0004-6361:200809813


A solar eruption triggered by merge interactions of different helicity loops

W. Song, X. Feng, and F. Shen

SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, PR China
    e-mail: [wbsong;fengx;fshen]@spaceweather.ac.cn

Received 20 March 2008 / Accepted 9 May 2008

Aims. We investigate the magnetic evolution of a flare/CME source region to determine the trigger of the flare and the EUV brightening event. Also, we discuss the role of the current helicity $(h_{\rm c})$ in solar activity.
Methods. We use the long duration sequences of SOHO/MDI magnetograms and TRACE 195 Å images for a super active region (AR), NOAA AR 8375. Magnetic field changes in the photosphere and the corona are investigated.
Results. In AR 8375, the southwestern and northwestern parts of an overlying loop ($h_{\rm c}$ < 0) are influenced by the rising magnetic arcades ($h_{\rm c}$ > 0) and the emerging flux region ($h_{\rm c}$ > 0). Two collisions make the overlying loop inflate in a bounce interaction. However, the related solar events are triggered by a merge interaction which takes place among the fibers of the rising magnetic arcades and among those of the overlying loop.

Key words: Sun: flares -- Sun: coronal mass ejections (CMEs) -- Sun: magnetic fields

© ESO 2008