Oscillatory behavior of chromospheric fine structures in a network and a semi-active regions

In the present work, we study the periodicities of oscillations in dark fine structures using observations of a network and a semi-active region close to the solar disk center. We simultaneously obtained spatially high resolution time series of white light images and narrow band images in the H$α$ line using the 2D Göttingen spectrometer, which were based on two Fabry-Perot interferometers and mounted in the VTT/Observatorio del Teide/Tenerife. During the observations, the H$α$ line was scanned at 18 wavelength positions with steps of 125 mÅ. We computed series of Doppler and intensity images by subtraction and addition of the H$α$ $\pm$ 0.3 Å and $\pm$ 0.7 Å pairs, sampling the upper chromosphere and the upper photosphere, respectively. Then we obtained power, coherence and phase difference spectra by performing a wavelet analysis to the Doppler fluctuations. Here, we present comparative results of oscillatory properties of dark fine structures seen in a network and a semi-active region.

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