Preliminary results of the search for helium nuclei in solar energetic events measured in the PAMELA experiment

Abstract

We presented the preliminary results of the search for helium nuclei in solar energetic events measured in the PAMELA experiment in the rigidity range from 0.1 to 1 GV from 2006 to 2014. We constructed selection criteria for helium nuclei and estimated their efficiency. The spectra are approximated using a simple power-law function and functional form based on Ellison-Ramaty, consisting of a power-law spectrum modulated by an exponential.