Extension of the Finite Integration Technique including dynamic mesh refinement and its application to self-consistent beam dynamics simulations

TL;DR

This paper extends the Finite Integration Technique with dynamic mesh refinement, improving efficiency in self-consistent beam dynamics simulations without sacrificing accuracy, demonstrated on RF gun modeling at DESY Zeuthen.

Contribution

It introduces a novel spline-based interpolation technique for mesh adaptation within the FIT framework, enhancing simulation efficiency for complex electromagnetic problems.

Findings

Adaptive mesh refinement achieves comparable accuracy to fixed mesh.

Dynamic mesh approach significantly reduces computational effort.

Application to RF gun modeling demonstrates practical benefits.

Abstract

An extension of the framework of the Finite Integration Technique (FIT) including dynamic and adaptive mesh refinement is presented. After recalling the standard formulation of the FIT, the proposed mesh adaptation procedure is described. Besides the linear interpolation approach, a novel interpolation technique based on specialized spline functions for approximating the discrete electromagnetic field solution during mesh adaptation is introduced. The standard FIT on a fixed mesh and the new adaptive approach are applied to a simulation test case with known analytical solution. The numerical accuracy of the two methods are shown to be comparable. The dynamic mesh approach is, however, much more efficient. This is also demonstrated for the full scale modeling of the complete RF gun at the Photo Injector Test Facility DESY Zeuthen (PITZ) on a single computer. Results of a detailed design study addressing the effects of individual components of the gun onto the beam emittance using a fully self-consistent approach are presented.