Energy loss for electrons in the Heliosphere and local interstellar spectrum for solar modulation

Galactic Cosmic Rays (GCR) entering the Heliosphere are a®ected by the solar modulation, a combination of di®usion, convection, magnetic drift and adiabatic energy loss usually seen as a decrease in the °ux at low energy (less than » 10 GeV). We have improved a quasi time-dependent 2D Stochastic Simulation code describing this e®ects. We focused our attention on the electron modulation, adding energy losses in the Heliosphere that can be neglected for protons and ions: inverse Compton, ionization, synchrotron and bremsstrahlung. These effects have been evaluated in the region affected by the solar magnetic field, up to 100 AU, where the environment conditions are not constant, especially the magnetic field intensity and the photon density. In our calculation the inverse compton energy losses are dominant, but they contribute only a few percent in comparison with the adiabatic losses. We also compared the Local Interstellar Spectrum (LIS) of primary electrons with experimental data collected in the past years at energies > 20 GeV. We found that, inside one standard deviation, LIS fits the data and can be used in a Monte carlo code reproducing CR propagation in the Heliosphere.