Platform of adaptive algorithms for global simulations of planetary space weather

We present a new free and open source (FOSS) simulation platform under development at the Finnish Meteorological Institute. Building on top of our existing space weather models for Earth, Mercury and other planets, the aim is to enable efficient global simulations of plasma interactions in the solar system and beyond, including unmagnetized and magnetized planetary bodies with and without atmospheres and ionospheres. Our development focuses on a flexible combination of magnetohydrodynamic (MHD), hybrid particle-in-cell (PIC) and full-kinetic methods. Fast time to solution is achieved via runtime adaptive mesh refinement (AMR), temporal substepping and massively parallel implementation using the message passing interface (MPI) and open multi-processing (OpenMP). We describe our approaches to combining different physical solutions within the same simulated volume and combining AMR with substepping. We verify the implementation against a plethora of test cases in one, two and three dimensions, and also discuss initial results from simulations of Mercury and BepiColombo flybys using particle and MHD approaches and highlight the largest differences.