First results on global hybrid-Vlasov magnetospheric simulations with a coupled ionosphere

Vlasiator, the global hybrid-Vlasov model of the terrestrial magnetosphere, now features a coupled ionosphere model replacing the previous, perfectly conducting inner boundary. Following a well-established approach, densities, temperatures and field-aligned currents are mapped along the geomagnetic dipole field down to an ionospheric grid. Height-integrated Hall and Pedersen conductivities are computed using a model atmospheric profile based on the NRLMSIS model in order to solve for the ionospheric potential. Its gradient is then mapped back to the hybrid-Vlasov simulation domain, yielding an electric field and a resulting EXB drift affecting the plasma at the boundary.

We present an overview of this new coupled ionosphere module as well as highlights from the first large-scale magnetospheric simulation runs performed with it. In particular, we compare the global behaviour of the magnetosphere under steady southward interplanetary magnetic field driving using the perfectly conducting or coupled ionosphere boundary models.