A Study of the Periodicities of Solar Filament Activity

Using the filament catalogues of Meudon Observatory, France, we have compiled a daily count sequence of filaments from July 1957 to December 2004 and carried out a periodicity analysis with the Scargle periodogram and Morlet wavelet transform. It is discovered that this sequence exhibits four evident periods: 1557, 1141, 795 and 367 days. The characteristics of the variations of these periods are analyzed in detail and the phases, physical mechanisms as well as the mutual relations of some of the periods are briefly discussed.