• G. Pöplau
  Rostock University, Faculty of Engineering, Rostock
• K. Floettmann
  DESY, Hamburg
• U. van Rienen
  Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock

Precise and fast 3D space-charge calculations for bunches of charged particles are still of growing importance in recent accelerator designs. A widespread approach is the particle-mesh method computing the potential of a bunch in the rest frame by means of Poisson's equation. Recently new algorithms for solving Poisson's equation have been implemented in the tracking code Astra. These Poisson solvers are iterative algorithms solving a linear system of equations that results from the finite difference discretization of the Poisson equation. The implementation is based on the software package MOEVE (Multigrid Poisson Solver for Non-Equidistant Tensor Product Meshes) developed by G. Pöplau. The package contains a state-of-the-art multigrid Poisson solver adapted to space charge calculations. In this paper the basic concept of iterative Poisson solvers is described. It is compared to the established 3D FFT Poisson solver which is a widely-used method for space charge calculations and also implemented in Astra. Advantages and disadvantages are discussed. Further the similarities and differences of both approaches are demonstrated with numerical examples.