Dynamics of the solar atmosphere. III - Cell-network distinctions of chromospheric oscillations

The propagation of waves in the chromosphere is analyzed, with focus placed on the differences between the bright boundaries of the chromospheric network and the dark cell interior. The logarithmic velocity and intensity power spectra of Ca 8542 and Ca 8498 are presented, along with the velocity fluctuations of Ca 8542 at a spatially resolved point in a cell center. Attention is focused on the phase difference and coherence spectra between the velocity fluctuations of Ca 8542 and Ca 8498 and Ca 8542 and the photospheric Fe 8496 line, as well as on the V - I phase and coherence spectra of the Ca lines. Significant differences in both power and phase spectra are found in the main power range from 3 to 6 mHz and also at low frequencies below 3 mHz and in the high-frequency range up to at least 10 mHz. It is shown that the evanescent waves are influenced by the magnetic field in the cell boundaries.