Plasmoid releases in the Saturn's magnetosphere

In this work, the interactions between the solar wind and the magnetosphere of Saturn are studied via state-of-the-art global MHD simulations, focusing on the release of plasmoids in the magnetotail. We analyze in detail the occurrence rate, the size, the speed and the evolution of the plasmoids in the simulations and compare the results with in-situ measurements. In our simulations, the multi-species three-dimensional MHD equations are solved with the code MPI-AMRVAC on a spherical non-uniform mesh ranging from 3 Rs (inner boundary) to 200 Rs (outer boundary). In order to simulate the magnetosphere-ionosphere coupling, to accelerate the ionospheric plasma up to rigid corotation and to close the electrical current systems, ion-neutral collisions are introduced in the MHD equations in the ionospheric region near the inner boundary. The strong mass-loading associated with the moon Enceladus is also included as an axisymmetric torus centered at 5.5 Rs.