Running waves in the sunspot chromosphere

Running waves at the chromospheric level (Hα) in sunspots are studied. Propagating 3-min oscillations are shown to be typical of many spots. Presumably, they propagate along the vertical magnetic-field lines. Their propagation speed is measured. According to our analysis, the 5-min oscillations propagating in the penumbral chromosphere are not a continuation of the 3-min umbral oscillations. The wavelength and propagation speed of the running penumbral waves are determined.