Cold, Supersonic Evershed Downflows in a Sunspot

Bibcode
2001ApJ...549L.139D
DOI
10.1086/319137
del Toro Iniesta, Jose Carlos; Bellot Rubio, Luis R.; Collados, Manuel
Bibliographical reference

The Astrophysical Journal, Volume 549, Issue 1, pp. L139-L142.

Advertised on:
3
2001
Journal
The Astrophysical Journal
Number of authors
3
IAC number of authors
2
Citations
81
Refereed citations
68
Description
We report here on the discovery of supersonic Evershed downflows in the penumbra of a sunspot. These flows are shown to occur along spatially unresolved, very cold magnetic flux tubes whose downflowing footpoints are found from the middle penumbra outward. Evershed flows along magnetic field lines returning to the solar surface were discovered by Westendorp Plaza and coworkers, but only in the outer parts of the penumbra and beyond its visible boundary; on the other hand, no supersonic flows of any type have ever been reported in the photosphere of sunspots, except for the very different case of the delta spot analyzed by Martínez Pillet and coworkers. We present unequivocal evidence of such supersonic motions, already predicted theoretically by the siphon-flow model, from the interpretation of infrared spectropolarimetric observations of a sunspot with unprecedented spatial resolution.
Type
Refereed
Magnetic fields
Sunspots
Techniques

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