Long-term Periodicities in the Flare Index between the Years 1966-2001

A brief description and the results of the temporal variability of the flare index over the epoch of almost 4 cycles (1966-2001) are presented. Using Fourier and wavelet transforms the long-term periodicities in the daily flare index data for the total surface and for the northern and the southern hemispheres of the Sun are presented. A significant variability was found for all periods. The wavelet transform results show that the occurrence of flare index power is highly intermittent in time.