Overview of the flare index during the maximum phase of the solar cycle 23

T. Atac (1), A. Ozguc (1), J. Rybák (2),

1 - Bogazici University, Kandilli Observatory and Earthquake Research Institute, Cengelkoy, Istanbul, Turkey
2 - Astronomical Institute, Slovak Academy of Sciences, SK-05960 Tatranská Lomnica, Slovakia

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 aris e 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 usin g 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 usin g the wavelet transform. The results of this transform show that during the maximum phase o f 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 determ ining the characteristics of the flare activity in the solar cycle 23.


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