摘要：Aims. The determination of the magnetic filed vector in solar filaments is made possible by interpreting the Hanle and Zeeman effects in suitable chromospheric spectral lines like those of the He Imultiplet at 10 830 Å. We study the vector magnetic field of an active region filament (NOAA 12087).Methods. Spectropolarimetric data of this active region was acquired with the GRIS instrument at the GREGOR telescope and studied simultaneously in the chromosphere with the He I10 830 Å multiplet and in the photosphere Si I10 827 Å line. As has been done in previous studies, only a single-component model was used to infer the magnetic properties of the filament. The results are put into a solar context with the help of the Solar Dynamic Observatory images.Results. Some results clearly point out that a more complex inversion had to be performed. First, the StokesVmap of He Idoes not show a clear signature of the presence of the filament. Second, the local azimuth map follows the same pattern as StokesV; it appears that polarity of StokesVis conditioning the inference to very different magnetic fields even with similar linear polarization signals. This indication suggests that the StokesVcould be dominated from below by the magnetic field coming from the active region, and not from the filament itself. This evidence, and others, will be analyzed in depth and a more complex inversion will be attempted in the second part of this series.
关键词：enSun: filaments, prominencesSun: chromosphereSun: magnetic fieldsSun: infraredSun: evolution
