PROPAGATING MAGNETOACOUSTIC WAVES IN THE SOLAR CHROMOSPHERE

We report on spectroscopic one dimensional observations showing for th e first time upward propagating 5 mn period waves, which emerge from t he deep chromospheric network. Wavetrains are well measured at the hei ght where the He I line (at lambda = 1083 nm) is formed by the coronal back radiation. We also present results from a time series of narrow filtergrams of a, quiet region at the disk center. The two dimensional mapping of the power of waves observed in the chromosphere shows the familiar cell-like distribution corresponding to the network magnetic field pattern. In addition, Fourier components with significantly long er periods than 5 mn were detected in the chromospheric network. We su ggest that the waves propagating in the open corona are reminescent of photospheric oscillations transmitted by the magnetic field of the ch romospheric network.