Evolution of fine structures in a filament

Abstract

A quiescent filament observed in June 1986 underwent a slow Disparition Brusque which lasted 4 days. Here, we focus our study on the dynamical behaviour of the fine structures ( Full-Width Half-Max ~ 350 km) in this filament which were observed at Pic du Midi with the Multi-Channel Subtractive Double Pass (MSDP) spectrograph during a period of 30 minutes. We observed no changes in intensity during this period, but we did observe changes in the velocity field with no correlation from one minute to the next. High velocities were detected at the footpoints where the filament is anchored in the photosphere , of the same order than those observed at the boundaries of the supergranules (between ±10 km s⁻¹). To explain these observations we suggest a spicule-like model which supplies material to the prominence.