Traces of Periodicity in the Observational Data on Magnetic Fields of Celestial Bodies and the Dynamo Models
- 10 Downloads
From the viewpoint of dynamo theory, periodic behavior of the magnetic field is interpreted as a manifestation of the eigenmode in magnetohydrodynamic equations describing the dynamo. The alternative explanation is that we are dealing with a demonstration of different fluctuations of the dynamo control parameters rather than with a periodic process. A simplified geodynamo model is considered; it is able to reproduce a scale of inversions that is similar to the real scale and a priori does not describe excitations of a periodically varying magnetic field. The analysis shows that, according to the currently available data on the scale of geomagnetic field polarities, the presence of a eigen frequency corresponding to a period of about 50 Ma is not fixed in the geodynamo problem.
This work was partially supported by the Russian Foundation for Basic Research, projects 18-02-00085 and 18-52-06002.
- 1.Frick, P., Galyagin, D., Hoyt, D.V., Nesme-Ribes, E., Schatten, K.H., Sokoloff, D., and Zakharov, V., Wavelet analysis of solar activity recorded by sunspot groups, Astron. Astrophys., 1997, vol. 328, pp. 670–681.Google Scholar
- 2.Galyagin, D.K., Reshetnyak, M.Yu., Sokolov, D.D., and Frick, P.G., Scaling of the geomagnetic field and scales of geomagnetic polarity, Dokl. Earth Sci., 1998, vol. 360, no. 4, pp. 617–620.Google Scholar
- 3.Gradstein, F.M., Ogg, J.G., Schmitz, M.D., and Ogg, G.M., The Geologic Time Scale 2012, Oxford: Elsevier, 2012, pp. 85–113.Google Scholar
- 4.Hathaway, D.H., The solar cycle, Living Rev. Sol. Phys., 2015, vol. 12, id 4.Google Scholar
- 8.Petrova, G.N., Nechaeva, T.B., and Pospelova, G.A., Kharakternye izmeneniya geomagnitnogo polya v proshlom (Characteristic Changes in the Geomagnetic Field in the Past), Moscow: Nauka, 1992.Google Scholar
- 9.Sobko, G.S., Zadkov, V.N., Sokoloff, D.D., and Trukhin, V.I.,, Geomagnetic reversals in a simple geodynamo model, Geomagn. Aeron. (Engl. Transl.), 2012, vol. 52, no. 2, pp. 254–260.Google Scholar