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

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.Comment: 33 pages, 14 figures, 4 table

UD Establishes Scholarship Fund to Help Student Who Lost Parents in Tornado

News release announces that a scholarship fund has been established to cover expenses for Ryan Cook\u27s remaining years at UD

Modeling of an electrically driven droplet generator

An electrohydrodynamic model for the simulation of droplet formation, mo- tion and detachment in an electrically driven droplet generator is introduced. The nu- merical approch is based on the coupled solution of the multiphase flow problem with the charge continuity equation. A conduction-convection model, taking into account con- ductive, capacitive and convective currents in the fluid, describes the charge relaxation phenomena in the moving liquid. The charge received by the droplets during acceleration by an external electric pulse is an important parameter influencing dynamics of droplets in the pressure chamber. The model is illustrated with simulations of detachment of high conductivity acetone droplets and low conductivity n-pentane droplets

Progress of the Development of a Superconducting Undulator as a THz Source for FELs

To produce radiation in the THz frequency range at X-ray Free Electron Lasers, undulators with large period length, high fields, and large gaps are required. These demands can be fulfilled by superconducting undulators. In this contribution, the actual requirements on the main parameters of such a superconducting undulator will be discussed and the progress of the design will be discussed. In addition, beam impedance and heat load results obtained analytically as well as by large-scale wakefield simulations will be presented

Investigation of Beam Impedance and Heat Load in a High Temperature Superconducting Undulator

The use of high temperature superconducting (HTS) materials can enhance the performance of superconducting undulators (SCU), which can later be implemented in free electron laser facilities, synchrotron storage rings and light sources. In particular, the short period < 10 mm undulators with narrow magnetic gap < 4 mm are relevant. One of the promising approaches considers a 10 cm meander-structured HTS tapes stacked one above the other. Then, the HTS tape is wound on the SCU. The idea of this jointless undulator has been proposed by, and is being further developed at KIT. Since minimizing the different sources of heat load is a critical issue for all SCUs, a detailed analysis of the impedance and heat load is required to meet the cryogenic system design. The dominant heat source is anticipated to be the resistive surface loss, which is one of the subjects of this study. Considering the complexity of the HTS tape, the impedance model includes the geometrical structure of the HTS tapes as well as the anomalous skin effect. The results of the numerical investigation performed by the help of the CST PS solver will be presented and discussed