Solar modulation of the spectra of protons and helium nuclei in the PAMELA experiment

Abstract

We present the energy spectra of protons and helium nuclei of cosmic rays obtained in the PAMELA experiment on board the satellite RESURS-DK1 for the period from August 2006 to December 2009. The spectra were measured in the energy range of 100 MeV/nucleon to 100 GeV/nucleon using a magnetic spectrometer within the apparatus. Variations in the solar modulation potential for protons and helium nuclei were calculated on the basis of the monthly mean particle fluxes. A force field model was used to compare the modulation with measurements from balloon experiments, and with measurements from a network of neutron monitors.