Entity: new gpu-enabled particle-in-cell code for extreme plasma astrophysics

Particle-in-cell has been a go-to approach for modeling plasmas in the environments of compact astrophysical objects for the last decade. Yet, there is no single publicly available code that includes all relevant radation-plasma coupling processes and is capable of modeling global systems. In this talk I will describe development of a new-generation PIC code for extreme astrophysical plasmas, Entity. The code is based on the Kokkos framework, which enables efficient implicit multi-architecture portability including GPUs. The code features algorithms for various radiation-plasma coupling processes, such as Compton scattering, production of electron-positron pairs and their annihilation. The code is designed in general coordinate system, defined by the metric functions; this enables the Entity to also efficiently tackle the global (full-system) models of the magnetospheres of compact objects, which require algorithms on non-cartesian (spherical, cubed sphere) non-uniform grids, and even full general relativity.