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Paper: Limb Prominences seen in UV, EUV and SXR
Volume: 369, New Solar Physics with Solar-B Mission
Page: 279
Authors: Heinzel, P.; Farnik, F.; Anzer, U.; Dammasch, I.
Abstract: We use SOHO/SUMER, EIT and Yohkoh/SXT prominence observations to study the absorption and/or volume blocking of UV, EUV and SXR coronal radiation by cool prominence plasma. An example of such a complex behaviour is the limb prominence observed on 5 September 1996. The SUMER spectrograph has detected two coronal lines, MgX at 625 Å which is absorbed by the hydrogen Lyman continuum and blocked within a volume occupied by cool prominence plasma, and FeXII at 1242 Å where the prominence appears dark due to blocking (no absorption at this wavelength). A similar behaviour show also the EUV images taken by EIT. We find that a darkening similar to that detected in the FeXII line is quite well visible also in the SXR images obtained by Yohkoh/SXT. To explain this feature, we exclude the absorption by the HeI and HeII resonance continua (hydrogen absorption is quite negligible) and suggest that it is entirely due to the volume blocking. Based on a quantitative analysis of these data, we discuss the physical conditions in cool prominences and their coronal environment. Finally, we propose new high-resolution EUV and SXR observations of prominences by Solar-B, using the EUV imaging spectrometer (EIS) and the X-ray telescope (XRT), respectively.
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