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| Titel |
The redshifted footpoints of coronal loops |
| VerfasserIn |
I. E. Dammasch, W. Curdt, B. N. Dwivedi, S. Parenti |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 26, no. 10 ; Nr. 26, no. 10 (2008-10-15), S.2955-2959 |
| Datensatznummer |
250016241
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| Publikation (Nr.) |
 copernicus.org/angeo-26-2955-2008.pdf |
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| Zusammenfassung |
| The physics of coronal loops holds the key to understanding coronal heating and
the flow of mass and energy in the region. However, the energy source,
structure maintenance and mass balance in coronal loops are not yet fully understood.
Observations of blue- and redshifted emissions have repeatedly been used in the
construction of loop models. But observations and interpretations of
line shifts have been widely debated. Here we present detailed SUMER observations,
which clearly show a steady downflow in both footpoints of coronal loops
observed at transition region (TR) and lower corona temperatures.
We also show and quantify a correlation existing between this
Doppler shift and the spectral radiance. Our results indicate a strong
correlation which holds from the chromosphere to the lower corona. We suggest that
the downflow in the footpoints may be a common phenomenon on all scales, which could
explain, why on a statistical basis bright pixels tend to be more redshifted.
We conclude by presenting interpretation of such results and their implications in
the light of a viable coronal loop model. The observation of steady downflow
in redshifted footpoints seems to be in conflict with impulsive heating. |
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