Parallel Asynchronous Simulations of High-Speed Magnetized Plasma Flows

Recent advances in computer technology and numerical algorithms have made it possible to model strongly kinetic parts of the Earth’s outer magnetosphere with hybrid and particle-in-cell codes. The critical issue in global magnetospheric simulations is efficient handing of disparate temporal scales which naturally arise in various regions of a large computational domain. Modern quasi-neutral hybrid simulations are capable of modeling both macroscopic (confinement, stability, translation) and microscopic (turbulence, reconnection and ion energization) properties of finite-beta plasmas. In conventional hybrid simulations of strongly inhomogeneous systems, however, the global timestep has to be often severely reduced in order to properly account for energetic/fast gyrating particles and generation of local high-frequency oscillations. We present a novel asynchronous, parallel discrete-event hybrid code that resolves these issues – HYPERS [1]. HYPERS does not step spatially distributed variables synchronously in time but instead performs time integration by executing discrete events: asynchronous updates of particles and fields carried out as frequently as dictated by local physical time scales. We demonstrate new numerical capabilities in 2D and 3D on challenging numerical problems that deal with high-speed magnetized plasma flows. We show that discrete-event simulations are remarkably fast and accurate compared to conventional hybrid simulations.