Advances in Multiscale Simulations of Solar Wind Interactions with the Earth's Magnetosphere

摘要

The accuracy of space weather forecasts critically depends on the availability of realistic models of the near-Earth environment driven by the solar wind. With advances in computer technology and numerical algorithms it has recently become possible to model strongly kinetic parts of the outer magnetosphere with hybrid and particle-in-cell codes. The critical issue in global simulations is efficient handling of disparate temporal and spatial scales. In conventional hybrid simulations the global time step has to be severely reduced in order to properly account for energetic/fast gyrating particles and fast whistler oscillations in high magnetic field/low density regions. Recently we introduced and validated a novel asynchronous, discrete-event hybrid code that resolves these issues: HYPERS. Here we report recent improvements to HYPERS and demonstrate its new capabilities by conducting simulations of the interaction of high-Mach solar wind flows with the Earth's magnetosphere formed for a nearly radial interplanetary magnetic field. We show that discrete-event simulations are capable of asynchronously resolving times scales differing by orders of magnitude.