WinGraphics: An Optimized Windowing Environment for Interactive Real-Time Simulations

We have developed a customized windowing environment, Win Graphics, which provides particle simulation codes with an interactive user interface. The environment supports real-time animation of the simulation, displaying multiple diagnostics as they evolve in time. In addition, keyboard and printer (PostScript and dot matrix) support is provided. This paper describes this environment

Improved Space Charge Modeling for Simulation and Design of Photoinjectors

Photoinjectors in advanced high-energy accelerators reduce beam energy spreads and enhance undulator photon fluxes. Photoinjector design is difficult because of the substantial differences in time and spatial scales. This Phase I program explored an innovative technique, the local Taylor polynomial (LTP) formulation, for improving finite difference analysis of photoinjectors. This included improved weighting techniques, systematic formula for high order interpolation and electric field computation, and improved handling of space charge. The Phase I program demonstrated that the approach was powerful, accurate, and efficient. It handles space charge gradients better than currently available technology

Improved Space Charge Modeling for Simulation and Design of Photoinjectors

Photoinjectors in advanced high-energy accelerators reduce beam energy spreads and enhance undulator photon fluxes. Photoinjector design is difficult because of the substantial differences in time and spatial scales. This Phase I program explored an innovative technique, the local Taylor polynomial (LTP) formulation, for improving finite difference analysis of photoinjectors. This included improved weighting techniques, systematic formula for high order interpolation and electric field computation, and improved handling of space charge. The Phase I program demonstrated that the approach was powerful, accurate, and efficient. It handles space charge gradients better than currently available technology

Analysis Code for High Gradient Dielectric Insulator Surface Breakdown

High voltage (HV) insulators are critical components in high-energy, accelerator and pulsed power systems that drive diverse applications in the national security, nuclear weapons science, defense and industrial arenas. In these systems, the insulator may separate vacuum/non-vacuum regions or conductors with high electrical field gradients. These insulators will often fail at electric fields over an order of magnitude lower than their intrinsic dielectric strength due to flashover at the dielectric interface. Decades of studies have produced a wealth of information on fundamental processes and mechanisms important for flashover initiation, but only for relatively simple insulator configurations in controlled environments. Accelerator and pulsed power system designers are faced with applying the fundamental knowledge to complex, operational devices with escalating HV requirements. Designers are forced to rely on “best practices” and expensive prototype testing, providing boundaries for successful operation. However, the safety margin is difficult to estimate, and system design must be very conservative for situations where testing is not practicable, or replacement of failed parts is disruptive or expensive. The Phase I program demonstrated the feasibility of developing an advanced code for modeling insulator breakdown. Such a code would be of great interest for a number of applications, including high energy physics, microwave source development, fusion sciences, and other research and industrial applications using high voltage devices

Progress in Parallelizing XOOPIC

X11-based Unix computers) is presently a serial 2d 3v particle-in-cell plasma simulation. This effort focuses on using parallel and distributed processing to optimize the simulation for large problems. The benefits include increased capacity for memory intensive problems, and improved performance for processor-intensive problems. The MPI library enables the parallel version to be easily ported to massively parallel, SMP, and distributed computers. The philosophy employed here is to spatially decompose the system into computational regions separated by “virtual boundaries”, objects which contain the local data and algorithms to perform the local field solve and particle communication between regions. This implementation reduces the impact of the parallel extension on the balance of the code. Specific implementation details such as the hiding of communication latency behind local computation will also be discussed, as well as code features and capabilities. 1 GOALS FOR PARALLEL XOOPIC XOOPIC has been successful as a single-processor code, and is able to simulate many interesting devices including relativistic klystron oscillators, electron guns, DC discharges with gas chemistry, plasma display panel cells, and highly relativistic beams in accelerators. However, particle-in-cell simulations are very computationally intensive, and on a single processor, some problems may take months to complete. The goals, therefore, for parallel XOOPIC are: Reduce run-times for large, complex simulations from weeks to days. Distribute memory demands across machines, allowing larger simulations than possible otherwise. Cross platform portability (networks of workstations, massively parallel machines, and SMP machines). Identical usage and feature set for parallel and nonparallel versions of XOOPIC, and largely shared source code. Complete source code availability to the general public