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Beam Dynamics



SciDAC-2: ComPASS Codes
Beam Dynamics
 
 
 
The aim of the Beam Dynamics component of the ComPASS project is to develop a comprehensive multi-physics framework for modeling the motion of charged particles in accelerators. The framework contains a suite of scalable beam dynamics codes and modules, with shared components, for modeling high order optics, a variety of collective phenomena (space charge, beam-beam effects, electron cloud effects, wakefield effects, etc.), intrabeam scattering, and other physical phenomena relevant to charged particle dynamics.

BeamBeam3D - A a multi-model parallel particle-in-cell (PIC) code for simulating colliding beams, including models for weak- strong, strong-strong, head-on, crossing angle, and long range effects. BeamBeam3d features an integrated Green function capability and a non-uniform grid Green function capability for modeling the oncoming beam's electromagnetic fields. It also has multi-slice, multi-bunch, and multi-IP capabilities. An impedance model and map generation from lattice function measurements capability were recently added for Tevatron modelling. Due to the large amount of particle movement between beam-beam collisions, traditional PIC code parallelization strategies (e.g. domain decomposition) are not used in the code. Instead, following a performance study of different approaches, we adopted a hybrid parallel decomposition for optimal performance. BeamBeam3D has been used to simulate colliding beams at the Tevatron, PEP-II, RHIC, and LHC. It has been successfully benchmarked against VEPP2 data.
 
IMPACT - The IMPACT code suite is widely used for modeling high intensity beams in rf proton and electron linacs and photoinjectors. It includes the 3D parallel PIC codes IMPACT-T and IMPACT-Z, along with a linac design code, an envelope code, and a number of pre- and post-processors. The code suite includes a number of useful features including a choice of parallel Poisson solvers to model space-charge effects, the ability to model high aspect ratio beams, the ability to model beams with ions of multiple charge states, and models for wakefield effects and a 1D model of coherent synchrotron radiation . The IMPACT suite has been used to model the SNS linac, the RIA driver linac, the fermi@elettra linac, the JPARC linac, and photoinjectors at BNL, FNAL, Cornell, and LCLS. It was used for the first-ever 1 billion particle simulations of a linac for a proposed future x-ray light source.
 
Synergia - A multi-language, extensible framework utilizing state-of-the-art numerical libraries, solvers, and physics models. Synergia features 3D space-charge and impedance modules, and arbitrary order Lie maps for magnetic optics (from the CHEF libraries). Selected features include multi-bunch, ramping and RF and magnet, multi-turn injection, and active feedback modeling. It utilizes multiple Poisson solvers including an FFT-based solver from IMPACT and a multigrid solver. Since compiling a hybrid code can be a complicated task which is further complicated by the diverse set of existing parallel computing environments, Synergia includes a build system that allows it to be compiled and run on various platforms without requiring the user to modify the code and/or build system. Furthermore, we have taken advantage of the Python scripting language to provide a flexible and powerful human user interface and means to control program flow. Synergia has been used to model the FNAL Booster, the CERN PS, and the ILC RTML.
 
MaryLie/IMPACT (ML/I) - A hybrid code that combines the high order beam optics capabilities of MaryLie with the parallel Particle-In-Cell capabilities of IMPACT. In addition to combining the capabilities of these codes, ML/I has a number of powerful features, including a choice of Poisson solvers, a fifth-order rf cavity model, multiple reference particles for rf cavities, a library of soft-edge magnet models, representation of magnet systems in terms of coil stacks with possibly overlapping fields, and wakefield effects. The code allows for map production, map analysis, particle tracking, and 3D envelope tracking, all within a single, coherent user environment. ML/I has a front end that can read both MaryLie input and input in the Standard Input Format. The code inherits the powerful fitting and optimizing capabilities of MaryLie, augmented for the new features of ML/I. The combination of soft-edge magnet models, high-order capability, space charge effects, and fitting/optimization capabilities, make ML/I a powerful code for a wide range of beam optics design problems. Along with LBNL and the University of Maryland (where IMPACT and MaryLie were respectively developed), other institutions involved in the ML/I code development effort include LANL, BNL, UCLA, and Tech-X Corporation.