The global polarization of $\Lambda$ and $\bar{\Lambda}$ has recently become a topic of great interest because it has been associated with the properties of the medium produced in relativistic heavy ion collisions. It has been studied the possibility that the global vorticity, produced in semi-central collisions, be estimated in terms of global polarization, since this is transferred to the degrees of freedom of spin, in particular the $\Lambda$ and $\bar{\Lambda}$ whose polarization can be measured through their decay. The Beam Energy Scan (BES) at RHIC, measured $\Lambda$ and $\bar{\Lambda}$ global polarization as a function of the collision energy. They observed that global polarization increases as the collision energy decreases, being greater the effect for the $\bar{\Lambda}$. Furthermore HADES Collaboration showed a preliminary result for $\Lambda$ polarization different from zero for collisions at $\sqrt{s_{NN}} = 2.42$ GeV. To describe this behavior of the polarization we develop the core-corona model, invoking the idea that these particles are produced in two different density zones, a high-density core and a less dense corona. We show that the relative abundance of $\Lambda$s coming from the core versus those coming from the corona influence the polarization. In this talk I show that the model predicts that both polarizations peak at collision energies $\sqrt{s_{NN}} < 10$ GeV, the energy range accessible to NICA and HADES.