Some effects of acoustic waves on spectral-line profiles.

We discuss the formation of spectral lines in the presence of short-period, nonlinear, radiatively damped acoustic waves propagating through a model of the solar atmosphere. The temperature and pressure perturbations associated with the wave strongly influence the line profile. Although their wavelength is less than the depth of the velocity response function of photospheric spectral lines, the acoustic waves produce large (> 100 ms), short-period line shifts. Acoustic waves of sufficient amplitude to account for chromospheric heating do not significantly increase the equivalent widths of photospheric lines and therefore are probably not responsible for photospheric microturbulence. Subject headings: line formation — line profiles — radiative transfer — Sun: atmosphere — Sun : atmospheric motions