Abstract
Simulating astrophysical plasmas is a grand challenge due to the extremely wide range of spatial and temporal scales of the systems. We present here HPC models of the evolution of the Earth space environment during geomagnetic storms. The phenomena span from tens of Earth radii in size down to scales as tiny as the motion of single particles. This challenge pushes our community at the cutting edge of HPC. Thanks to the computational resources provided by PRACE Tier-0 we were able to overcome these challenges and obtain some key new discoveries. All the simulations are performed with the fully kinetic implicit Particle-in-Cell code iPIC3D (Markidis et at. 2010), whose implicitness allows us to describe the particles behavior within an acceptable computational time. This code presents a great scalability up to tens of thousand cores and beyond, as well as a minimal use of so-called "bottleneck operations", such as collective communications.