Numerical simulation of plasmas on an unstructured grid

The use of unstructured grids provides some inherent advantages in the accurate simulation of plasma problems that involve complex configurations and where the treatment of complicated boundaries is important. The use of a triangular grid in two dimensions and of a tetrahedral grid with arbitrary connectivity in three dimensions allows a straightforward representation of complex geometries and allows the resolution of the mesh to vary according to the requirements of a problem. The authors have constructed a very simple and efficient data structure to represent unstructured grids for geometries with arbitrarily shaped boundaries. The data contains information about the location of vertices, edges, sides, and cells and permits with one degree of indirectness the implementation of algorithms for field solvers and for particle orbit integration. The numerical algorithms that have been constructed include a potential solver, an electromagnetic solver for both the time and frequency domain, and a particle-in-cell simulation. The efficiency and vectorization of the basic code functions are retained and yield timing results comparable with structured mesh codes.