Vlasiator is a global magnetospheric simulation code based on a hybrid-Vlasov description of plasma, where ions are represented by a six-dimensional distribution function, while electrons are modeled as a charge neutralizing fluid. The model provides uniformly discretized ion velocity distribution functions with quality comparable to spacecraft measurements.
In this presentation Vlasiator and its numerical implementation is detailed: To propagate the distribution function we use a finite volume method, coupled to an upwind constrained transport method for propagating electromagnetic fields. We have parallelized the code with a two-level MPI and OpenMP scheme, and it scales well to tens of thousands of cores. The hybrid-Vlasov approach is enabled through a novel sparse representation of the distribution function that reduces the problem size by more than two orders of magnitude. Additionally, first results are shown from global five-dimensional magnetospheric simulations