The heliospheric Modulation od Cosmic ray Electrons: Rigidity Dependence of the perpendicular Diffusion Coefficient

Abstract

The modulation of cosmic ray electrons in the heliosphere provides a useful tool in understanding and estimating the diffusion tensor applicable to heliospheric modulation. Using a comprehensive modulation model including all major mechanisms to study electron modulation, especially at energies below 500 MeV, we found that perpendicular diffusion is very important to electron modulation at these energies. Electrons respond directly to the energy dependence of the diffusion coefficients below 500 MeV, in contrast to protons which experience large adiabatic energy losses below this energy. As a result of this and because drifts become unimportant for electrons at these low energies, important conclusions can be made about the absolute values, spatial and especially the rigidity dependence of the diffusion coefficients.