Distributed Mesh Infrastructure for Particle-in-Cell Simulations

Particle-in-cell (PIC) methods are an effective tool for fusion plasma simulations. In PIC the particle motion is influenced by the mesh fields and the mesh fields are influenced by particle locations. In applications with complex geometries and varying fields, there is a desire to employ unstructured meshes. Since the operations on the particles dominate computation and memory, particles are always distributed. Although it has been common to maintain a copy of the mesh in each memory space across the parallel computer, the need for higher accuracy for more complex systems is driving a need to also distribute the mesh. This presentation will overview PUMIpic, a distributed unstructured mesh infrastructure to support PIC calculations. PUMIpic employs a distributed mesh with overlap to avoid communication during a push, coordinated gather/scatter, parallel mesh field solve and adjacency-based containment search. The presentation will also discuss the status of two fusion plasma simulation codes being developed using PUMIpic.