Estimation of the effects of the Earth's electric and magnetic fields on cosmic muons at sea level by Geant4

We have investigated effects of the Earth's electric and magnetic fields on the cosmic muon fluxes at sea level using the Geant4 simulation package. Energies and fluxes of the primary protons and alpha particles incident on the modeled atmosphere were obtained from the balloon measurements. We have observed that the electric field at fair weather has no significant effect on the muon fluxes in the absence of the magnetic field. On the other hand, when electric field is not applied, the magnetic field seems to noticeably change both μ−μ− and μ+μ+ fluxes, especially below 1 GeV of muon energy for primaries coming from the Eastern and Western directions. When both electric and magnetic fields are applied, the situation is very similar to the case when only the magnetic field is on.

► Effects of the Earth's electric and magnetic fields on cosmic muon flux are studied using Geant4.
► The electric field at fair weather has no significant effect on the muon flux at sea level.
► The magnetic field noticeably changes flux of the muons with energy below 1 GeV at sea level.
► Effect of the magnetic field on muons is greater for the primaries coming from the East and the West.