In this work we have found out such a sequence of physical processes which allowed us to reveal the cause-and-effect relationship between the observed poloidal alternating magnetic field of the Sun and a factor of a non-electromagnetic nature, which is external to the Sun. Specific character of the Sun's orbital motion about the Solar system barycenter promotes emergence inside the Sun of the conditions necessary for generation of the observed poloidal component of the Sun's magnetosphere without participation of the Sun's own rotation. Using a pendulum as a model, we have shown in what way the external impact upon the Sun initiates within the Sun itself forced oscillations which are just those that induce the poloidal alternating magnetic field; in its turn, this magnetic field defines the cyclic character of the Wolf numbers. We have also revealed a process which allowed putting into consideration a natural event-time scale that may be quite useful in planning the observations and also in systematizing and synchronizing fragments of the available time series of observations manifesting the Sun's poloidal magnetic field about 20 years in period. Keywords: Sun's poloidal magnetic field, inversion, pole flip, barycenter, Jupiter, Saturn, Wolf numbers