High dispersion spectroscopy of quiescent prominences

A systematic study of the internal horizontal (line-of-sight) motions of quiescent prominences which were observed at the limb has been made by using fourier techniques to analyse the shift of the Ca ii K line as a function of height above the limb. The results indicate that a characteristic size for the velocity elements is present in 70% of the 13 prominences studied. This size of 4700 km is attributed to Alfvén waves induced by horizontal convective motions in the photosphere as previously suggested by Malville. The qualitative aspects of the observations are described by a simple model which is based on this hypothesis.Presently at Department of Astronomy, Pennsylvania State University, 525 Davey Lab., University Park, PA 16802.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.