A Detailed Analysis of an Ephemeral Region .

Guglielmino, S. L.; Martínez Pillet, V.; Ruiz Cobo, B.; Zuccarello, F.; Lites, B. W.
Bibliographical reference

Memorie della Società Astronomica Italiana Supplement, v.9, p.103 (2006)

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In order to improve the understanding of the process of emergence of magnetic flux on the solar surface, we studied the temporal evolution of an ephemeral region using emph{Advanced Stokes Polarimeter} data. We adopted two different approaches: first, we used a Milne-Eddington inversion to obtain mean parameters of the emerging bipole magnetic configuration. Then, we considered the full radiative transfer equation, and we studied the trend of all the previous parameters as a function of the optical depth tau . We pointed out peculiar flows, such as an initial upflow of 1.5 ;textrm {km s}-1 where the zenith angle is essentially horizontal, and downflows decreasing in time in footpoints, characterized by a vertical field. These results seem to confirm the emerging bipole topology, due to magnetic flux tube emergence. The results obtained with this inversion confirm the structure found with Milne-Eddington code. However we found regions in which the presence of two distinct magnetic components is highly significant. It also seems very interesting the trend of the temperature with optical depth: the plasma temperature appears to grow up in the high photosphere above the emerging bipole.