Mapping of the polar cap ionosphere by solar and magnetospheric particles

Abstract

Global magnetohydrodynamic (MHD) simulations have been successful in describing systems where the important spatial scales are larger than ion inertial length and the plasma has a well-defined temperature. The weakness of global one-fluid MHD simulations is their inability to model the multi-temperature, multi-component plasmas in the inner magnetosphere, where most of space-borne technology, including communication and navigation systems reside. We are developing a global hybrid-Vlasov simulation, where electrons are MHD fluid, but protons are modeled as distribution functions evolved in time using the Vlasov equation. This approach does not include the noise present in kinetic-hybrid simulations, but is computationally extremely challenging requiring petascale computations with thousands of cores. Here, we briefly review the status of our new parallel six-dimensional Vlasov solver. We carry out a test particle simulation and propagate the distribution functions using the electromagnetic fields of the GUMICS-4 global MHD simulation. Our main goal is to test the Vlasov solver in a global setup against the standalone GUMICS-4 global MHD simulation. The results shown here are obtained during due northward interplanetary magnetic field (IMF). We find that the magnetosheath and magnetopause plasma properties from the test particle simulation are in rough agreement with the results from the GUMICS-4 simulation. Furthermore, we show that the cusp injection patterns reproduce the expected behavior of northward IMF. The results indicate that our solver behaves sufficiently well, indicating that global hybrid-Vlasov simulations of this kind are feasible, promising improved global simulation capabilities in the future.