Photoelectric observations of chromospheric sunspot oscillations. V. Penumbral oscillations

Observations of penumbral magneto-atmospheric oscillations in which both the spatial and temporal behavior are measured simultaneously in two spectral lines (Fe I 5434 A and Ca II 8498 A) formed at widely separated heights in the atmosphere are analyzed. It is found that no single theoretical model can account for the variations in both strength and orientation of the magnetic field with radial distance from the center of the spot, with height in and below the penumbral photospehre, and on small spatial scales (penumbral filamentation). 29 references