Recurrent flares in active region NOAA 11283

Journal Article

2015

Published in: http://www.aanda.org/articles/aa/abs/2015/10/aa25887-15/aa25887-15.html

co-author, A. Elmhamdi . 2015

In order to shed light on the occurrence of recurrent flares and subsequent associated CMEs, we study the active region NOAA 11283 where recurrent M and X GOES-class flares and CMEs occurred. 
We use vector magnetograms taken by HMI/SDO to calculate the horizontal velocity fields of the photospheric magnetic structures, the shear and the dip angles of the magnetic field, the magnetic helicity flux distribution, and the Poynting fluxes across the photosphere due to the emergence and the shearing of the magnetic field. 

We conclude that the very long duration (about 4 days) of the horizontal displacement of the main photospheric magnetic structures along the PIL has a primary role in the energy release during the recurrent flares. This peculiar horizontal velocity field also contributes to the monotonic injection of magnetic helicity into the corona. This process, coupled with the high shear and dip angles along the main PIL, appears to be responsible for the consecutive events of loss of equilibrium leading to the recurrent flares and CMEs.

• Volume Number: Volume 582
• Magazine \ Newspaper: Astronomy & Astrophysics