Fourier analysis of chromospheric fine structures in two different regions

In this work, we study the periodicities of dark fine structures using observations of a quiet and a semi-active region close to the solar disc centre. Using the 2D spectrometer which was based on two Fabry-Perot interferometers and mounted at the Göttingen Vacuum Tower Telescope during that time, we obtained spatially high resolution time series of white light images and narrow band filtergrams simultaneously in the Hα line. During the observations, this line was scanned at 18 wavelength points with steps of 125 mÅ. We used the lambdameter method in order to get series of velocity and intensity images corresponding to different height levels in the solar atmosphere. Then, to obtain power spectra, Fourier analysis was performed to intensity and velocity fluctuations. Here, we present comparative results of dynamic properties of fine structures seen in a network and a semi-active region.