Investigation of Energy Spectrum of Semidiurnal Variations of Cosmic Rays

Abstract

An energy spectrum of semidiurnal variations of cosmic rays observed at the Earth is investigated. The data of registration of cosmic rays by the ground and underground multidirectional muon telescopes (stations Yakutsk, Nagoya, Hobart, Kuwait, São Martinho da Serra, Misato, Sakashita, Matsushiro), which covers the time period from 1971 to 2018 and the median energy range from 55 to 686 GeV, are used. Average annual values of semidiurnal variations of cosmic rays observed by the mentioned stations and free from atmospheric and geomagnetic effects are obtained. Based on the analysis of the obtained data, a form and temporal dynamics of their energy spectrum are investigated. It is established that the energy spectrum reveals dependence on the solar activity cycle.