We analyze time sequences of photospheric spectral lines in the penumbra of two sunspots. Two spectral lines sensitive to velocity fluctuations at two different...

The uncombed penumbral model proposed by Solanki & Montavon (cite{sol93a}) is used to understand some recent observational results found in penumbrae. This...

The conservation of magnetic flux demands a magnetic field fine structure as small as 15 km to explain the net circular polarization observed in penumbrae...

A combination of two penumbral models similar to those used by Martínez Pillet (2000) is presented. One matches the observed rms fluctuations perfectly while...

The way in which the effect of the instrumental polarization of a spectrograph can distort the shape of the intensity profiles in sunspots is shown empirically...

Velocity oscillations in sunspot umbrae have been measured simultaneously in two spectral lines: the photospheric Si I λ10827 line and the chromospheric He I...

Stokes profiles of sunspot penumbrae show distinct asymmetries, which point to gradients in the velocity field and in the magnetic field. We present...

We report on high angular resolution, high-precision spectropolarimetric measurements of a decaying sunspot. The spot gradually lost its penumbra during the...

Profiles of the Na I D doublet in three bright features (clusters of umbral dots), located in a relatively dark umbra, were analyzed by means of the 'local two...