Magnetospheric Response to a Pressure Pulse in a Three-dimensional Hybrid-Vlasov Simulation

Vlasiator is a high-performance ion-kinetic code that is now conducting global 3D hybrid-Vlasov simulations of the outer magnetosphere.  We use Vlasiator to investigate the impact of a pressure pulse with southward-oriented magnetic field on the Earth's magnetosphere. The simulation driving parameters are comparable to conditions that have led to real geomagnetic storms. Our pressure pulse simulations reproduce many physical effects, namely the expansion of the auroral oval, the development of field-aligned currents, enhanced particle precipitation near the open/closed field line boundary, and compression of Earth's magnetopause. This demonstrates the effectiveness of the hybrid-Vlasov approach for moderate driving conditions. Our investigation of the time-dependent magnetopause compression motivates a generalization of the existing theory. Specifically, we find that accounting for the finite ramp time of the solar wind dynamic pressure improves the model's description of the magnetopause oscillations.