Oscillations in presence of local magnetic fields

Oscillatory Doppler shifts in sunspots and in small fluxtubes are observed using either the intensity profile of lines with negligible magnetic splitting or the circular Zeeman profile of lines with strong Zeeman splitting. Sunspot umbrae show local 5 min oscillations of reduced amplitude as compared to the neighbouring photosphere. Occasionally we find 5 min oscillations of opposite phase at both outer penumbral borders. This could be interpreted as tilting and bobbing of the spot as a whole on the oscillating solar surface. In contrast to these larger scale sunspot fluxtubes the gas in the small fluxtubes of a few hundred km diameter seems to fully participate in the photospheric oscillations without any interaction with the magnetic field. Prominence magnetic fields show sometimes a reaction to the photospheric 5 min and to the chromospheric 3 min oscillations, in addition several other periods are found. Indication is found for eigenmodes of Alfven waves