Velocity structure and variations in the region of quiet solar filaments

We study the velocity fields in the region of quiet solar filaments using spectral observations at the Sayan Solar Observatory (ISTP, Irkutsk). Once the series of spectral images have been processed, maps of the two-dimensional distribution of the velocity and its variations in the chromosphere (in the Hβ λ = 486.13 nm line) and the photosphere (in the Fe I λ = 486.37 nm line) are constructed. The motions in the filaments have been found to consist of steady and periodic components. Our analysis of the spatial distributions of various oscillation modes shows that the short-period (<10 min) oscillations propagate mainly vertically and are observed at the filament edges, on scales of several arcseconds. The quasi-hour (>40 min) oscillations propagate mostly along the filament at a small angle to its axis. The intensity in the Hβ core in individual fragments of some filaments varies with a period of about one hour. The observed velocity structures in the filaments and the imbalance of steady motions on the opposite sides of the filaments can be explained in terms of the model of a twisted fine-structure magnetic flux tube.