Towards a Semi-Analytical Model of the Long-Term Variations of the Heliospheric Structures

When developing a model to accurately predict the solar modulation of galactic cosmic rays, it is crucial to consider the global characteristics of the heliosphere. The dynamics and variability of the boundaries of the heliosphere have a significant impact on the long-term variation of cosmic rays, even at Earth's location. Therefore, it is highly desirable to have a global, time-dependent, and user-friendly heliospheric structure modelization. With this aim, we developed a semi-analytical, data-driven model that uses a simplified approach for solving the solar wind dynamics through the heliosphere, including the effect of the pick-up ions on the termination shock. The model also uses measurements of the energetic neutral atoms' spectra at 1AU to determine the distance of the heliopause. The model's predictions have been compared with the observations of the Voyager probes.