  The observed variability of the cosmic-ray intensity in the interplanetary
space is driven by the evolution of the Sun's magnetic activity over its
11-year quasiperiodical cycle. Investigating the relationship between solar
activity indices and cosmic-ray intensity measurements is then essential for
understanding the fundamental processes of particle transport in the
heliosphere. Here we have performed a global characterization the solar
modulation of cosmic rays over the solar activity cycle and for different
energies of the cosmic particles. We present our cross-correlation studies
using data from space experiments, neutron monitors and solar observatories
collected over several solar cycles.
