Solar Wind Effects on the Transport of 3–10 MeV Cosmic‐Ray Electrons from Solar Minimum to Solar Maximum

Abstract

We investigate the effects on the transport of a few MeV (~7 MeV) Jovian and Galactic electrons for different solar wind speed scenarios applicable to different heliospheric conditions. A three-dimensional, steady state model is used based on numerically solving Parker's transport equation, including the Jovian electron source, to compare model computations to low-energy 3-10 MeV KET electron observations along the Ulysses trajectory. We show that, in general, the solar cycle-related variation in the latitude dependence of the solar wind speed significantly influences the three-dimensional transport of Jovian electrons in the inner heliosphere; in fact, we argue that to improve the interpretation of the Ulysses observations from solar minimum to solar maximum conditions, realistic latitudinal changes in the solar wind speed profile are needed. Decreasing the latitude dependence of the solar wind speed toward solar maximum results in more Jovian electrons and fewer Galactic electrons being computed at higher heliolatitudes. At Earth these changes influence the phase and amplitude of the 13 month periodicity in the computed electron intensities.