  Aims. To study intensity oscillations in the solar chromosphere/corona above
a quiet-Sun magnetic network. Methods. We analyse the time series of He II
256.32, Fe XI 188.23 and Fe XII 195.12 spectral lines observed by EUV Imaging
Spectrometer (EIS) on board Hinode near the south pole. Then we use a standard
wavelet tool to produce power spectra of intensity oscillations above the
magnetic network. Results. We get ~7 min intensity oscillations in all spectral
lines and ~13 min intensity oscillations only in He II with the probability of
~96-98 %, which probably reflects the process of magneto-acoustic wave
propagation above the network. Conclusions. We suggest that field-free cavity
areas under bipolar magnetic canopies in the vicinity of magnetic network may
serve as resonators for the magneto-acoustic waves. The cavities with
photospheric sound speed and granular dimensions may produce the waves with the
observed periods. The waves may propagate upwards in the transition
region/corona and cause observed intensity oscillations.
