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1

Multi-wavelength observations of flares and eruptive filaments

Zuccarello F., Contarino L., Romano P., Battiato V., Guglielmino S.

Acta Geophysica

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2009

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Vol. 57, no. 1

24-30

EN

In this paper we report some results obtained from multi-wavelength observations carried out to study the mechanisms operating in flares and filament eruptions. Most of these studies have given indication of the presence of phenomena that might be considered signatures of magnetic reconnection, while others have pointed out the important role played by magnetic helicity transport in corona before the eruptive phase.

2

Flare forecasting based on sunspot-groups characteristics

Contarino L., Zuccarello F., Romano P., Spadaro D., Guglielmino S., Battiato V.

Acta Geophysica

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2009

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Vol. 57, no. 1

52-63

EN

Our comprehension of solar flares is still lacking in many aspects and the possibility of observing active regions during the first phases of flare occurrence is limited by our capability of doing accurate flare forecasting. In order to give a contribution to this aspect, we focused our attention on the characteristics that must be fulfilled by sunspot-groups in order to be flare-productive. We addressed this problem using a statistical approach: first, we analyzed sunspot-groups parameters (i.e., Zürich class, magnetic configuration, area, morphology of the penumbra) and evolution; then, we performed a flare forecasting campaign, based on the results obtained in the first phase and on real-time observations. The results obtained by comparing the flare forecasting probability with the number of flares that have actually occurred are quite encouraging; we plan to improve this procedure by including a bigger statistical sampling.

3

Emergence and evolution of active and ephemeral regions: Comparison between observations and models

Zuccarello F., Guglielmino S., Battiato V., Contarino L., Spadaro D., Romano P.

Acta Geophysica

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2009

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Vol. 57, no. 1

15-23

EN

This work aims to describe some aspects relevant to the emergence of magnetic structures on the solar surface. Using high resolution photospheric and chromospheric data, besides than EUV images acquired by space telescopes, the dynamics of rising flux tubes is studied. It is shown that, for both long-lived and short-lived magnetic regions, the flux tubes are initially characterized by a high rising velocity, which eventually decreases as the region develops. Other results concern the timeline of the active regions appearance in the atmospheric layers and the asymmetries in plasma downflows between preceding and following legs of the flux tubes. These results are briefly discussed in the light of most recent models.