5 Conclusion

Figure 8: Characteristic lines generated by solar phenomena in a) the minimum and b) the rising phase of solar cycle 23. The three group of lines are inicated: the level of darkness qualitatively illustrate the importance of lines.

To summarise, our analysis of radio observations gives the majority of the known periods, reveals a clear difference among periodicities observed in the two phase of the solar cycle examined and shows that daily measured radio fluxes at various frequencies are very useful for the systematic study of solar periodicities observed in the different layers of the solar atmosphere. We are preparing a similar analysis for the next phases of solar cycle 23: the maximum and the declining phase.

We found the rotation rate of the "active longitudes" in the rising phase as equal to 444.4 $\pm$ 4 nHz (26 $.\!\!^{\rm d}$0 $\pm$ 0 $.\!\!^{\rm d}$3). We suppose that this period can be identified with a fundamental period of unknow Sun's clock as a lot of the known periodicities are subharmonics of it. We think that in the minimum the lines observed are conected with the small and large-scale magnetic fields which then dominate, while in the rising phase most lines are generated by new magnetic structures connected with long lived active regions formed within "active longitudes".

To understand the cause of all the observed periodicities, we still need new observational data, but more careful analyse of old radio data can also be useful (in preparation). However, our investigation, indicates that the solution of the observed solar periodicities should be sought in a complicated Sun's magnetic system which generate in the different solar data the compound set of solar periodicities.

Acknowledgements

First of all, we would like to thank our anonymous referee for very valuable remarks and suggestions which helped us to significantly improve the current version of the paper. The autors are grateful to Dr. K. Chyzy for assistance in preparation of the manuscript. This work was supported in partly by KBN grant No. 158/E - 338/SPUB - 204/93.