Anomalous Polarization Profiles in Sunspots: Possible Origin of Umbral Flashes

Bibcode
2000Sci...288.1396S
DOI
10.1126/science.288.5470.1396
Socas-Navarro, H.; Trujillo Bueno, J.; Ruiz Cobo, B.
Bibliographical reference

Science, Volume 288, Issue 5470, pp. 1396-1398 (2000).

Advertised on:
5
2000
Journal
Science
Number of authors
3
IAC number of authors
3
Citations
67
Refereed citations
59
Description
We present time-series spectropolarimetric observations of sunspots in the Ca II infrared triplet lines, which show a periodic occurrence of anomalous, asymmetric, circular polarization profiles in the umbral chromosphere. The profiles may be caused by the periodic development of an unresolved atmospheric component in a downward flowing magnetized environment. This active component with upward directed velocities as high as 10 kilometers per second is connected to the umbral flash (UF) phenomenon. We can explain the observations with a semiempirical model of the chromospheric oscillation and of the sunspot magnetized atmospheric plasma during a UF event.
Type
Refereed

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