Reconstruction of the magnetic connection from Mercury to the solar corona, during events in the solar proton fluxes observed by MESSENGER

We present a study conducted on a number of selected events characterised by a significant increase in the solar proton fluxes measured by FIPS-MESSENGER during the period 2011-2013. For each of them, the magnetic connection between Mercury and the solar corona (Source Surface Field @2.5 R_S) has been reconstructed, in order to identify the possible source of the accelerated particles on the solar surface. The transport of the magnetic field lines in the heliosphere is here evaluated with a Monte Carlo code that computes a random displacement at each step of the integration along the Parker magnetic field model. Such displacement is proportional to a “local” diffusion coefficient, which is a function of the fluctuation level and magnetic turbulence correlation lengths. The simulation is tailored to the specific events by using the observed values of solar wind velocity and magnetic fluctuation levels.