Homologous flares in AR 10486 on 27 October 2003

LUONI, M.L.; MANDRINI, C.H.; CRISTIANI, G.; DÉMOULIN, P.

Capilla del Monte, Córdoba, Argentina

Congreso; 49 Reunión de la Asociación Argentina de Astronomía; 2006

Active region (AR) NOAA 10486, together with 10484 and 10488, formed the largest and most complex activity group during solar cycle 23. AR 10486 produced eight GOES X-class solar flares and  many minor ones, such as the two M-class flares studied here. These events took place on 27 October 2003 with 3 hours difference. The events were homologous, as well as homologous to the event  that accompanied the X17 flare on 28 October 2003 (Mandrini et al., 2006). For the analysis we have used data in different  wavelenghts from the photosphere to the solar corona. The three events are similar and they occur in the same magnetic configuration, which is characterized by the presence of a magnetic field null point. Studying the magnetic field topology, deduced after modelling the coronal field,  we propose that the release of free  magnetic energy at this null gives place to the two flares  on the 27 and to the minor event on 28 October. The existence of this null point at the same location  during 2 days shows that this topological structure is stable.