An Interpretation of the Spectra of Surge Prominences. I. Velocity Field in the Disk Surge Observed on August 27, 1971

Abstract

A large surge on the solar disk was observed on August 27, 1971. In this paper, preliminary results concerning the three dimensional velocity fields in this surge are reported. As this surge was seen to develop in a direction along the entrance slit of the spectrograph, the motion of masses in the surge can be traced on a time series of the spectrograms. It is shown that the surge can be regarded as an explosive ejection, and the masses ascend with various initial velocities and then descend freely, perhaps along lines of force of the local magnetic field. The apparent features of the surges in several monochromatic observations are interpreted on the basis of our model.