A New Scenario of Solar Modulation Model during the Polarity Reversing

Abstract

When the Galactic Cosmic Rays (GCRs) entering the heliosphere, they encounter the solar wind plasma, and their intensity is reduced, so called solar modulation. The modulation is caused by the combination of a few factors, such as the particle energies, solar activity and solar disturbance. In this work, a 2D numerical method is adopted to simulate the propagation of GCRs in the heliosphere with SOLARPROP, and to overcome the time consuming issue, the machine learning technique is also applied. With the obtained proton local interstellar spectra (LIS) based on the observation from Voyager 1 and AMS-02, the solar modulation parameters during the solar maximum activity of cycle 24 have been found. It shows the normalization and index of diffusion coefficient indeed reach a maximal value in February 2014. However after taking into account the travel time of particles with different energies, the peak time found postponed to November 2014 as expected. The nine-month late is so called time lag.