A 2D STOCHATSIC MONTECARLO FOR THE SOLAR MODULATION OF GCR: A PROCEDURE TO FIT INTERPLANETARY PARAMETERS COMPARING TO THE EXPERIMENTAL DATA

We realized a 2 dimensional (radius and latitude) stochastic MonteCarlo for modelling the Galactic Cosmic Ray (GCR) propagation in the Heliosphere. The model solves numerically the transport equation of particles in the heliosphere, including major processes affecting the heliospheric particle transport: diffusion, convection, adiabatic energy losses and drift of particles. We estimated the cosmic rays spectrum at 1AU using this model formalism: our method allows the study of modulation behaviour in dependence on energy of interstellar particles and heliosphere parameters as Solar wind speed and the tilt angle α of the neutral sheet. We compared our simulations with the Primary CR proton spectra measured by AMS and we realized a fine tuning of our parameters in order to match real data. This work, done for the A > 0 period, can be done also for A < 0, where the best value found for the diffusion coefficient is different.