Symmetric spline weighting for charge and current density in particle simulation

A general method for computing charge and current density source terms for Maxwell's equations from particles weighted to a mesh is described. The met hod presented here eliminates the need for correction factors often applied in curvilinear coordinates to compensate for errors at the edge of the sys tem, and applied in the interior as well for nonuniform meshes. Generality is achieved by weighting volume elements using a spline symmetric to that b y which particle charge and current are weighted to the mesh. The method pr esented has a number of desirable properties, including conservation of cha rge, preservation of a uniform distribution, and generality on nonuniform m eshes with arbitrary particle-mesh interpolation schemes. The method recove rs the exact answer in the limit of mesh sizes approaching zero. (C) 2001 E lsevier Science.