منابع مشابه
Fine structure, magnetic field and heating of sunspot penumbrae
We interpret penumbral filaments as due to convection in field-free, radially aligned gaps just below the visible surface of the penumbra, intruding into a nearly potential field above. This solves the classical discrepancy between the large heat flux and the low vertical velocities observed in the penumbra. The presence of the gaps causes strong small-scale fluctuations in inclination, azimuth...
متن کاملField - Free Gaps near Τ = 1 in Sunspot Penumbrae ?
The vertical stratification of the magnetic field strength in sunspot penumbrae is investigated by means of spectropolarimetric observations at high spatial resolution from the Hinode spacecraft. Assuming that the magnetic field changes linearly with optical depth we find that, in those regions where the magnetic field is more inclined and the Evershed flow is strongest (penumbral intraspines),...
متن کاملA Curious History of Sunspot Penumbrae
Daily records of sunspot group areas compiled by the Royal Observatory, Greenwich, from May of 1874 through 1976 indicate a curious history for the penumbral areas of the smaller sunspot groups. On average, the ratio of penumbral area to umbral area in a sunspot group increases from 5 to 6 as the total sunspot group area increases from 100 to 2000 μHem (a μHem is 10−6 the area of a solar hemisp...
متن کاملRecent Evidence for Convection in Sunspot Penumbrae
Whereas penumbral models during the last 15 years have been successful in explaining Evershed flows and magnetic field inclination variations in terms of flux tubes, the lack of contact between these models and a convective process needed to explain the penumbral radiative heat flux has been disturbing. We report on recent observational and theoretical evidence that challenge flux tube interpre...
متن کاملThe multi-component field topology of sunspot penumbrae A diagnostic tool for spectropolarimetric measurements
Context. Sunspot penumbrae harbor highly structured magnetic fields and flows. The moving flux tube model offers an explanation for several observed phenomena, e.g. the Evershed effect and bright penumbral grains. Aims. A wealth of information can be extracted from spectropolarimetric observations. In order to deduce the structure of the magnetic field in sunspot penumbrae, detailed forward mod...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2009
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/200913074