Fast Particle Tracking With Wake Fields

TL;DR

This paper presents a method to efficiently incorporate wake field effects into particle tracking simulations by approximating wake functions with Taylor coefficients, enabling faster calculations of beam dynamics.

Contribution

It introduces a novel approach to approximate wake functions with Taylor coefficients for efficient particle tracking in electromagnetic fields.

Findings

The method accurately models wake field effects in particle tracking.

Application to an undulator beam pipe shows significant emittance growth prediction.

The approach reduces computational complexity compared to full electromagnetic simulations.

Abstract

Tracking calculations of charged particles in electromagnetic fields require in principle the simultaneous solution of the equation of motion and of Maxwell's equations. In many tracking codes a simpler and more efficient approach is used: external fields like that of the accelerating structures are provided as field maps, generated in separate computations and for the calculation of self fields the model of a particle bunch in uniform motion is used. We describe how an externally computed wake function can be approximated by a table of Taylor coefficients and how the wake field kick can be calculated for the particle distribution in a tracking calculation. The integrated kick, representing the effect of a distributed structure, is applied at a discrete time. As an example, we use our approach to calculate the emittance growth of a bunch in an undulator beam pipe due to resitive wall wake field effects.