Greg Schussman

X-BAND LINEAR COLLIDER R&D IN ACCELERATING STRUCTURES THROUGH ADVANCED COMPUTING ∗

This paper describes a major computational effort that addresses key design issues in the high gradient accelerating structures for the proposed X-band linear collider, GLC/NLC. Supported by the US DOE’s Accelerator Simulation Project, SLAC is developing a suite of parallel electromagnetic codes based on unstructured grids for modeling RF structures with higher accuracy and on a scale previously not possible. The new simulation tools have played an important role in the R&D of X-Band accelerating structures, in cell design, wakefield analysis and dark current studies.

State of the art in electromagnetic modeling for the Compact Linear Collider

SLACs Advanced Computations Department (ACD) has developed the parallel 3D electromagnetic time-domain code T3P for simulations of wakefields and transients in complex accelerator structures. T3P is based on state-of-the-art Finite Element methods on unstructured grids and features unconditional stability, quadratic surface approximation and up to 6 th -order vector basis functions for unprecedented simulation accuracy. Optimized for large-scale parallel processing on leadership supercomputing facilities, T3P allows simulations of realistic 3D structures with fast turn-around times, aiding the design of the next generation of accelerator facilities. Applications include simulations of the proposed two-beam accelerator structures for the Compact Linear Collider (CLIC) - wakefield damping in the Power Extraction and Transfer Structure (PETS) and power transfer to the main beam accelerating structures are investigated.

Scientific Discovery through Advanced Visualization

The SciDAC program of the Department of Energy has brought together tremendous scientific expertises and computing resources to realize the promise of terascale computing for attempting to answer some of the most important basic science questions. Scientific visualization is an indispensable path to gleaning insight from the massive data produced by terascale simulations. Unless the visualization challenges presented by the terascale simulations be adequately addressed, the value of conducting these immense and costly simulations is not being fully realized. In this paper, we introduce several key visualization technologies that address the critical need of many SciDAC scientists in the application areas from accelerator simulations, earthquake modeling, plasma physics, supernova modeling, to turbulent combustion simulations.

Enabling technologies for petascale electromagnetic accelerator simulation

The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations.

Achievements in ISICs/SAPP collaborations for electromagnetic modeling of accelerators

SciDAC provides the unique opportunity and the resources for the Electromagnetic System Simulations (ESS) component of High Energy Physics (HEP)s Accelerator Science and Technology (AST) project to work with researchers in the Integrated Software Infrastructure Centres (ISICs) and Scientific Application Pilot Program (SAPP) to overcome challenging barriers in computer science and applied mathematics in order to perform the large-scale simulations required to support the ongoing R&D efforts on accelerators across the Office of Science. This paper presents the resultant achievements made under SciDAC in important areas of computational science relevant to electromagnetic modelling of accelerators which include nonlinear eigensolvers, shape optimization, adaptive mesh refinement, parallel meshing, and visualization.

High‐Fidelity RF Gun Simulations with the Parallel 3D Finite Element Particle‐In‐Cell Code Pic3P

SLAC’s Advanced Computations Department (ACD) has developed the first parallel Finite Element 3D Particle‐In‐Cell (PIC) code, Pic3P, for simulations of RF guns and other spacecharge dominated beam‐cavity interactions. Pic3P solves the complete set of Maxwell‐Lorentz equations and thus includes space charge, retardation and wakefield effects from first principles. Pic3P uses higher‐order Finite Element methods on unstructured conformal meshes. A novel scheme for causal adaptive refinement and dynamic load balancing enable unprecedented simulation accuracy, aiding the design and operation of the next generation of accelerator facilities. Application to the Linac Coherent Light Source (LCLS) RF gun is presented.

Visualizing electromagnetic field and particle simulations in accelerators with ParaView

SLAC performs large-scale simulations of Electromagnetic fields and particles for accelerator applications. These simulations run on intricate high order finite element meshes and produce field strengths spanning tens of orders of magnitudes. Such simulations can pose challenges to visualization aiming to capture and present important features of the data in a distinct and efficient way. This paper records lessons learned while using ParaView to generate animations for multipacting, wakefield, and power flow simulations, and from experience gained in generating a 3D Stereo animation.