Overview of the flare index during the maximum phase of the solar cycle 23 Original Research Article

A brief description and final results of the flare index of solar activity for the maximum phase of the cycle 23 are given. The patterns of similar activity indices that arise under different physical conditions during the cycle 23 were compared with the flare index. The intermediate-term periodicities in the daily flare index data for the full disc and for the northern and the southern hemispheres of the Sun were calculated before by the authors using the Fourier transform, and it was found that 64, 125 days periodicities are in operation during the maximum phase of the solar cycle 23. In this paper, we examined these periodicities in time domain by using the wavelet transform. The results of this transform show that during the maximum phase of the current solar cycle a very prominent multi-peaked structures exist in each solar hemisphere and the occurrence of flare index power is highly intermittent in time. Moreover, it is found that the flare activity of the opposite hemispheres were not well time-synchronized during the maximum phase. The flare activity of the southern hemisphere was observed to be more dominant in determining the characteristics of the flare activity in the solar cycle 23.