Analytical studies of solar cycle 23 and its periodicities

Solar cycle 23 (now well under way) started in April 1996 and had its peak in the year 2000. Monthly counts of grouped solar flares during its entire period (launch on 1996 to re-entry on September 2000) are given. The data are obtained from Solar Geophysical data reports by NOAA national data centers, Boulder, Colorado, USA. The 10.7 cm radio flux during solar cycle 23 until September 2000 is also used in the present analysis. The periodicities around 1.4 years, 153.9, 105.3, 68, 53.6, and 46.9 days, have been recorded in this work and are significant. The 153.9 day-periodicity has been reported during solar cycle 23 in this work, while it was absent in previous papers during solar cycles 21 and 22. These periodicities are related to the theoretical mode of solar activity and of solar core oscillations.