Abstract:
Wave propagation in the nonmagnetic chromosphere is described for plane and spherical waves, and excitation by means of impulses in small source regions in the photosphere; excitation for flux tube waves in the magnetic network is described for large, single impulses and for a fluctuating velocity field. Observational signatures of the various wave types and their effect on chromospheric heating are considered. It is concluded that calcium bright points in the nonmagnetic chromosphere are due to spherical acoustic waves, and that for the oscillations in the magnetic network, transverse waves are more important than longitudinal waves; they may penetrate into the corona, giving rise to some coronal heating.