Paper detail

On the causes and mechanisms of the long-term variations in the GCR characteristics

We argue that the degree of understanding the causes and mechanisms of the long-term variations (11-year and 22-year) in the galactic cosmic rays (GCR) characteristics is still insufficient and to improve it we need new approaches and methods. For the time being there is a long-lasting controversy on how these long-term variations, observed for more than 50 years in the inner heliosphere, are formed. It is widely believed that the 11-year variation is due entirely to the toroidal branch of solar activity (the area and number of sunspots, the strength of the heliospheric magnetic field etc) because of the diffusion, convection and adiabatic energy loss, while the much smaller 22-year variation is caused by the particle drifts connected with the poloidal branch of solar activity (the high-latitude solar magnetic fields). At the same time, both past and more recent numerical simulations indicate that the contribution of particle drifts could be significant for both 22- and 11-year variations in the GCR intensities. However, even those who agree on the significant influence of drifts appear to have different perceptions on the mechanisms of this influence. In this paper, we present an analysis of the possible causes of the first point of view (small role of drifts in the 11-year GCR variation) and the reasons why one can expect the significant contri- bution of the processes connected with the poloidal branch of solar activity in both types of the long-term variations of the GCR characteristics. Then we briefly discuss some numerical methods suggested in the past and recently and the approaches and perspectives for the sought-for methods are considered.