3D SPACE CHARGE CALCULATIONS FOR BUNCHES IN THE TRACKING CODE ASTRA

Precise and fast 3D space charge calculations for bunches of charged particles are of growing importance in recent accelerator designs. One of the possible approaches is the particle-mesh method computing the potential of the bunch in the rest frame by means of Poisson’s equation. Fast methods for solving Poisson’s equation are the direct solution applying Fast Fourier Transformation (FFT) and a finite difference discretization combined with a multigrid method for solving the resulting linear system of equations. Both approaches have been implemented in the tracking code Astra. In this paper the properties of these two algorithms are discussed. Numerical examples will demonstrate the advantages and disadvantages of each method, respectively.