A 3D Monte Carlo calculation of the inverse Compton emission from the Sun and stars in presence of electro-magnetic field

The steady gamma-ray emission of the Sun is due to the interactions of Galactic Cosmic Rays with the solar atmosphere and with the low-energy solar photon field via inverse Compton scattering. Cosmic rays travel through the solar system and scatter with the interplanetary magnetic field carried by the solar wind, so the gamma-ray emission is expected to be sensitive to the electro-magnetic field in the corona and in the heliosphere. Modeling the inverse Compton emission in the presence of a magnetic field is therefore crucial to better interpret the observations. In a previous work we have presented a comprehensive calculation of the secondary productions due to the collision of cosmic rays with the solar atmosphere in presence of magnetic fields. In this paper, we present a general approach to calculate the (anisotropic) inverse Compton scattering in a 3D Monte Carlo simulation, also in presence of magnetic and electric fields. The inverse Compton emission for the Sun is presented and discussed.