Evidence for supersonic downflows in the photosphere of a delta sunspot

Bibcode
1994ApJ...425L.113M
DOI
10.1086/187323
Martinez Pillet, V.; Lites, B. W.; Skumanich, A.; Degenhardt, D.
Referencia bibliográfica

Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 425, no. 2, p. L113-L115

Fecha de publicación:
4
1994
Revista
Astrophysical Journal
Número de autores
4
Número de autores del IAC
1
Número de citas
42
Número de citas referidas
36
Descripción
We present polarization profiles observed with the High Altitude Observatory/National Solar Observatory (HAO/NSO) Advanced Stokes Polarimeter (ASP) that demonstrate, in a model-independent way, the presence of strong downflows close to the neutral line of a delta sunspot (a spot with both polarities contained within the same penumbra). The flows are as large as 14 km/s, a velocity that, at photospheric levels, strongly suggests the presence of supersonic compressive fluid flows in a region only 100-200 km above the visible surface. These velocities are probably the largest ever reported at photospheric levels. The region containing the downflows is large enough (about 2 sec on a side) to be resolved, although it is likely to contain fine structure at or below our spatial resolution. The origin of these flows is discussed in terms of the funneling of material through an isolated magnetic nozzle in an otherwise closed magnetic system which is rising through the surface.
Tipo
Con árbitro
Polarímetros
Manchas solares
Modelos astronómicos

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