Alternating-Order Interpolation in a Charge-Conserving Scheme for Particle-In-Cell Simulations

We discuss the interpolation of the electric and magnetic fields within a charge-conserving Particle-In-Cell scheme. The choice of the interpolation procedure for the fields acting on a particle can be constrained by analyzing conservation of the energy and the particle generalized momentum. The better conservative properties are achieved, if the alternating-order form-factor is used for interpolation, which combines the lower-order and higher-order interpolation from integer and semi-integer points of a staggered grid. This approach allows us to significantly reduce noise in the charge conserving scheme and improves both the results quality and the computational efficiency.