On determining the microturbulent velocities of solar prominences

The classical method for determining the velocities of microturbulent motions in solar prominences is generalized to account for the possible opacity of the spectral lines. A new characteristic of a line is introduced which, for a given line formation mechanism, can be used to determine the optical...

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Veröffentlicht in:Astrophysics 2010-07, Vol.53 (3), p.387-395
Hauptverfasser: Nikoghossian, A. G., Mouradian, Z.
Format: Artikel
Sprache:eng
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Zusammenfassung:The classical method for determining the velocities of microturbulent motions in solar prominences is generalized to account for the possible opacity of the spectral lines. A new characteristic of a line is introduced which, for a given line formation mechanism, can be used to determine the optical thickness of the emitting region. The method is applied to lines in the EUV region observed with the SUMER spectrograph as part of the SOHO space program. Comparison with observational data not only confirms the validity of this mechanism for line formation, but also shows that the optical thickness of the medium is small for these lines. Difficulties involved in determining the kinetic temperature and, therefore, the microturbulent velocities, are discussed. Based on lines of various ions, this velocity is estimated to be on the order of 30–40 km/s.
ISSN:0571-7256
1573-8191
DOI:10.1007/s10511-010-9130-0