Project NEPTUNE approaches one of the grand challenge problems in fusion - modelling plasma in the edge region of a tokamak. In this edge region, hot plasma interfaces with the reactor wall and cold neutral gas resulting in a computationally expensive multi-scale problem that is considered an exascale challenge. We apply finite elements as a discretisation over physical space and use a particle representation as a kinetic representation in velocity space.
In this talk we discuss NESO-Particles (NP), our particle framework, which is a library for describing particle data and looping operations on unstructured meshes. We provide a high-level API in which users can describe generic particle, grid and global properties for their simulation. Furthermore we provide a particle specific loop abstraction which separates the description of particle looping operations from their respective implementation on CPU and GPU hardware.