Knowledge of the past solar activity is important for predicting the future solar activity. One of the key quantities characterizing the solar activity is the solar modulation parameter (SMP). It parameterizes solar activity by the use of equation that describes the propagation of cosmic rays in the solar system. SMP for the last few decades is determined using neutron monitors. Cosmogenic isotopes are commonly used to obtain information on SMP beyond the instrumental period. We used data on the Be production rate for the last 9.5 thousand years. According to Kovaltsov and Usoskin 2010, there is an unambiguous relationship between the Be production rate, the geomagnetic field strength, and SMP. We used this relationship to determine the solar modulation parameter for the Holocene. It is shown that the time dependence of SMP is non-stationary. For further analysis, the empirical mode decomposition method was applied Huang et al., 2003. Analysis of the modes obtained showed that among the younger modes, there are cycles with periods of 710 and 208 years. The latter mode is a manifestation of the De Vries cycle known in the analysis of cosmogenic isotopes. The existence of a cycle with a period of 710 years cannot be explained within the framework of standard concepts of cosmogenic isotopes. We associate the existence of the 710-year cycle with fluctuations in the tilt of the Earth’s magnetic dipole. It is shown that, taking into account the influence of the dipole tilt fluctuations on the formation rate of cosmogenic isotopes, the De Vries cycle in the Holocene was the dominant low-frequency cycle with a period of about a hundred years. The wavelet analysis showed that its amplitude remained virtually unchanged for 9.5 thousand years. The aim of the work is to study the cyclicity of solar activity taking into account the existence of fluctuations in the tilt of the Earth’s magnetic dipole.
S.S. Vasiliev (2025) studied this question.