Variability and Dynamics of the Outer Atmospheric Layers in the Quiet Solar Network

Abstract

A detailed study of the temporal evolution of the chromospheric He I 584.33 Å and the transition region O V 629.73 Å emission line intensities of quiet supergranular network of the Sun near disk centre observed with Coronal Diagnostic Spectrometer (CDS) is presented. A wavelet analysis of the 1729 s (28.8 min) long temporal series was performed in order to derive the duration as well as periods of the chromospheric and the transition region oscillations. The He I line intensities show significant power for periods around 300 s (3.3 mHz), which is relevant only in the second half of the observing sequence (between 800 -- 1700 s). The temporal evolution corresponding to the O V line intensities shows strong power around the period of 400 s (2.5 mHz), which is significant during the whole observing sequence as well as the oscillation of lower power for periods of around 250 s (4.0 mHz), which is present only in the middle of the observing sequence (between 700 -- 1300 s).