Spectral diagnostics of the magnetic field orientation in a round-shaped filament

TitleSpectral diagnostics of the magnetic field orientation in a round-shaped filament
Publication TypeConference Paper
Year of Publication2002
AuthorsSchmieder, B., Mein N., Heinzel P., and Anzer U.
EditorWilson, A.
Conference NameSolar Variability: From Core to Outer Frontiers
Date PublishedDec

During several campaigns focused on prominences we have obtained coordinated spectral observations from the ground and from space. The SOHO/SUMER spectrometer allows us to observe, among others, the whole Lyman series of hydrogen, while the Hα line was observed by the MSDP spectrograph at the VTT. For Lyman lines, the non-LTE radiative-transfer computations have shown the importance of the prominence-corona transition region (PCTR) and its relation to the magnetic field orientation for the explanation of the observed line profiles (Schmieder et al. 1998, Heinzel et al. 2001). Moreover, Heinzel and Anzer (2001) developed new 2D models which demonstrate how the shapes of Lyman lines vary depending on the orientation of the magnetic field with respect to the line of sight. To confirm this result observationally, we focus here on a round-shaped filament observed during three days as it was crossing the limb. The Lyman profiles observed on the limb are different from day to day and we interpret these differences by the change of orientation of the prominence axis (and therefore the magnetic field direction) with respect to the line-of-sight.