Talk abstract

Several phenomena may occur in different layers of the solar atmosphere when the new magnetic flux emerges and interacts with the pre-existing ambient field. The appearance of surges and brightenings during flux emergence is a clear evidence of the magnetic reconnection process, at work in the emergence site because of the rearrangement in the magnetic topology. We analyze a small-scale flux emergence episode, occurred in NOAA 10971, observed simultaneously by the Hinode satellite and the Swedish Solar Telescope in La Palma Island. G-band, Hα, and Ca II H images, together with Fe I and Na I magnetograms, EUV raster scans, and XRT filtergrams show that the emerging region is associated with a Hα chromospheric surge and Ca II H, Hα, EUV and X-ray brightenings. We find also magnetic flux cancellation occurring in the lower atmospheric layers. We discuss this event within the framework of the low-altitude magnetic reconnection model. At this purpose, we also present a series of force-free extrapolations, calculated with the FROMAGE code, which show that the emergence site spatially coincides with a 3D null point, from which a spine originates. Such a magnetic configuration is comparable with the structures observed in the different atmospheric layers.