INVESTIGADORES
MANDRINI Cristina Hemilse
artículos
Título:
Topological analysis of emerging bipole clusters producing violent solar events
Autor/es:
MANDRINI, C.H.; SCHMIEDER, B.; DÉMOULIN, P.; GUO, Y.; CRISTIANI, G.
Revista:
SOLAR PHYSICS
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2014 vol. 289 p. 2041 - 2071
ISSN:
0038-0938
Resumen:
During the rising phase of Solar Cycle 24 tremendous activity occurred
on the Sun with rapid and compact emergence of magnetic flux leading to
bursts of flares (C to M and even X-class). We investigate the violent
events occurring in the cluster of two active regions (ARs), NOAA
numbers 11121 and 11123, observed in November 2010 with instruments
onboard the Solar Dynamics Observatory and from Earth. Within one day
the total magnetic flux increased by 70 % with the emergence of new
groups of bipoles in AR 11123. From all the events on 11 November, we
study, in particular, the ones starting at around 07:16 UT in GOES soft
X-ray data and the brightenings preceding them. A magnetic-field
topological analysis indicates the presence of null points, associated
separatrices, and quasi-separatrix layers (QSLs) where magnetic
reconnection is prone to occur. The presence of null points is confirmed
by a linear and a non-linear force-free magnetic-field model. Their
locations and general characteristics are similar in both modelling
approaches, which supports their robustness. However, in order to
explain the full extension of the analysed event brightenings, which are
not restricted to the photospheric traces of the null separatrices, we
compute the locations of QSLs. Based on this more complete topological
analysis, we propose a scenario to explain the origin of a low-energy
event preceding a filament eruption, which is accompanied by a
two-ribbon flare, and a consecutive confined flare in AR 11123. The
results of our topology computation can also explain the locations of
flare ribbons in two other events, one preceding and one following the
ones at 07:16 UT. Finally, this study provides further examples where
flare-ribbon locations can be explained when compared to QSLs and only,
partially, when using separatrices.