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Parallel Simulation Algorithms for the Three Dimensional Strong-Strong Beam-Beam Interaction

Description: The strong-strong beam-beam effect is one of the most important effects limiting the luminosity of ring colliders. Little is known about it analytically, so most studies utilize numeric simulations. The two-dimensional realm is readily accessible to workstation-class computers (cf.,e.g.,[1, 2]), while three dimensions, which add effects such as phase averaging and the hourglass effect, require vastly higher amounts of CPU time. Thus, parallelization of three-dimensional simulation techniques is imperative; in the following we discuss parallelization strategies and describe the algorithms used in our simulation code, which will reach almost linear scaling of performance vs. number of CPUs for typical setups.
Date: March 17, 2008
Creator: Kabel, A. C.
Partner: UNT Libraries Government Documents Department

A C++ Framework for Conducting High-Speed, Long-Term Particle Tracking Simulations

Description: For the purpose of conducting parallel, long-term tracking studies of storage rings such as the ones described in [3], [4], maximum execution speed is essential. We describe an approach involving metaprogramming techniques in C++ which results in execution speeds rivaling hand-optimized assembler code for a particular tracking lattice while retaining the generality and flexibility of an all-purpose tracking code.
Date: February 6, 2006
Creator: Kabel, A. C.
Partner: UNT Libraries Government Documents Department

A Multi-Bunch, Three-Dimensional, Strong-Strong Beam-Beam Simulation Code for Parallel Computers

Description: For simulating the strong-strong beam-beam effect, using Particle-In-Cell codes has become one of the methods of choice. While the two-dimensional problem is readily treatable using PC-class machines, the three-dimensional problem, i.e., a problem encompassing hourglass and phase-averaging effects, requires the use of parallel processors. In this paper, we introduce a strong-strong code NIMZOVICH, which was specifically designed for parallel processors and which is optimally used for many bunches and parasitic crossings. We describe the parallelization scheme and give some benchmarking results.
Date: May 11, 2005
Creator: Cai, Y. & Kabel, A. C.
Partner: UNT Libraries Government Documents Department

Peak Current Optimization for LCLS Bunch Compressor 2

Description: In this study, we calculate the effects of Coherent Synchrotron Radiation (CSR) in the LCLS bunch compression section BC2[3] on the resulting FEL performance, considering a realistic, strongly non-gaussian longitudinal charge distribution. The longitudinal chirping required for the bunch compression process leads to a non-linear, non-monotonous {delta}(z) functional dependence (Fig. 1 shows the current distribution and the energy offset along the bunch). We model this functional dependence by matching it to a cubic polynomial {delta} {approx} c{sub 0} + c{sub 1}z + c{sub 2}z{sup 2} + c{sub 3}z{sup 3}. During compression, the charge distribution in the z-{delta} plane will ''fold over'', as shown in fig. 2. This leads to a cusp at each end of the current distribution I(z), as shown in figure 3. High |l'(z)| values will lead to high longitudinal CSR fields, with possible detrimental effects on the transverse projected and slice emittance as well as energy spread, possibly affecting FEL performance.
Date: May 9, 2005
Creator: Emma, P. & Kabel, A. C.
Partner: UNT Libraries Government Documents Department

Long-Term Simulation of Beam-Beam Effects in the Tevatron at Collision Energy

Description: The beam-beam effect is a significant source of nonlinearities in the Tevatron. We have developed a code which allows us to estimate its contribution to the finite lifetime of the anti-proton beam, both at collision and injection energy, by tracking realistic particle distribution for a high number of terms and extrapolating from the particle loss rate. We describe the physical modeling underlying the code and give benchmarking results.
Date: February 10, 2006
Creator: Kabel, A.C.; Cai, Y.; /SLAC; Sen, T. & /Fermilab
Partner: UNT Libraries Government Documents Department

A Parallel Code for Lifetime Simulations in Hadron Storage Rings in the Presence of Parasitic Beam-Beam Interactions

Description: The usual approach to predict particle loss in storage rings in the presence of nonlinearities consists in the determination of the dynamic aperture of the machine. This method, however, will not directly predict the lifetimes of beams. We have developed a code which can, by parallelization and careful speed optimization, predict lifetimes in the presence of 100 parasitic beam-beam crossings by tracking > 10{sup 10} particles-turns. An application of this code to the anti-proton lifetime in the Tevatron at injection is discussed.
Date: March 17, 2008
Creator: Kabel, A. C.; Cai, Y.; Erdelyi, B.; Sen, T. & Xiao, M.
Partner: UNT Libraries Government Documents Department

Applications of Parallel Computational Methods to Charged-Particle Beam Dynamics

Description: The availability of parallel computation hardware and the advent of standardized programming interfaces has made a new class of beam dynamics problems accessible to numerical simulations. We describe recent progress in code development for simulations of coherent synchrotron radiation and the weak-strong and strong-strong beam-beam interaction. Parallelization schemes will be discussed, and typical results will be presented.
Date: October 16, 2007
Creator: Kabel, A.; Cai, Y.; Dohlus, M.; Sen, T. & Uplenchwar, R.
Partner: UNT Libraries Government Documents Department

Experimental Characterization of the Transverse Phase Space of a 60-MeV Electron Beam Through a Compressor Chicane

Description: Space charge and coherent synchrotron radiation may deteriorate electron beam quality when the beam passes through a magnetic bunch compressor. This paper presents the transverse phase-space tomographic measurements for a compressed beam at 60 MeV, around which energy the first stage of magnetic bunch compression takes place in most advanced linacs. Transverse phase-space bifurcation of a compressed beam is observed at that energy, but the degree of the space charge-induced bifurcation is appreciably lower than the one observed at 12 MeV.
Date: February 12, 2007
Creator: Zhou, F.; Kabel, A.; Rosenzweig, J.; Agustsson, R.; Andonian, G.; Cline, D. et al.
Partner: UNT Libraries Government Documents Department

SciDAC advances in beam dynamics simulation: from light sources to colliders

Description: In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of SciDAC-II accelerator project,"Community Petascale Project for Accelerator Science and Simulation (ComPASS)." Several parallel computational tools for beam dynamics simulation will be described. A number of applications in current and future accelerator facilities, e.g., LCLS, RHIC, Tevatron, LHC, ELIC, are presented.
Date: June 16, 2008
Creator: Qiang, Ji; Qiang, J.; Borland, M.; Kabel, A.; Li, R.; Ryne, R. et al.
Partner: UNT Libraries Government Documents Department

Parallel Computation of Integrated Electromagnetic, Thermal and Structural Effects for Accelerator Cavities

Description: The successful operation of accelerator cavities has to satisfy both rf and mechanical requirements. It is highly desirable that electromagnetic, thermal and structural effects such as cavity wall heating and Lorentz force detuning in superconducting rf cavities can be addressed in an integrated analysis. Based on the SLAC parallel finite-element code infrastructure for electromagnetic modeling, a novel multi-physics analysis tool has been developed to include additional thermal and mechanical effects. The parallel computation enables virtual prototyping of accelerator cavities on computers, which would substantially reduce the cost and time of a design cycle. The multi-physics tool is applied to the LCLS rf gun for electromagnetic, thermal and structural analyses.
Date: November 2, 2011
Creator: Akcelik, V.; Candel, A.E.; Kabel, A.C.; Ko, K.; Lee, L.; Li, Z. et al.
Partner: UNT Libraries Government Documents Department

Parallel Computation of Intergrated Electronmagnetic, Thermal and Structural Effects for Accelerator Cavities

Description: The successful operation of accelerator cavities has to satisfy both rf and mechanical requirements. It is highly desirable that electromagnetic, thermal and structural effects such as cavity wall heating and Lorentz force detuning in superconducting rf cavities can be addressed in an integrated analysis. Based on the SLAC parallel finite-element code infrastructure for electromagnetic modeling, a novel multi-physics analysis tool has been developed to include additional thermal and mechanical effects. The parallel computation enables virtual prototyping of accelerator cavities on computers, which would substantially reduce the cost and time of a design cycle. The multi-physics tool is applied to the LCLS rf gun for electromagnetic, thermal and structural analyses.
Date: July 2, 2008
Creator: Akcelik, V.; Candel, A.; Kabel, A.; Lee, L-Q.; Li, Z.; Ng, C-K. et al.
Partner: UNT Libraries Government Documents Department

Parallel 3D Finite Element Numerical Modelling of DC Electron Guns

Description: In this paper we present Gun3P, a parallel 3D finite element application that the Advanced Computations Department at the Stanford Linear Accelerator Center is developing for the analysis of beam formation in DC guns and beam transport in klystrons. Gun3P is targeted specially to complex geometries that cannot be described by 2D models and cannot be easily handled by finite difference discretizations. Its parallel capability allows simulations with more accuracy and less processing time than packages currently available. We present simulation results for the L-band Sheet Beam Klystron DC gun, in which case Gun3P is able to reduce simulation time from days to some hours.
Date: February 4, 2008
Creator: Prudencio, E.; Candel, A.; Ge, L.; Kabel, A.; Ko, K.; Lee, L. et al.
Partner: UNT Libraries Government Documents Department

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

Description: 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 space-charge 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 Elementmethods 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.
Date: June 19, 2009
Creator: Candel, A; Kabel, A.; Lee, L.; Li, Z.; Limborg, C.; Ng, C. et al.
Partner: UNT Libraries Government Documents Department

OBSERVATION OF LONG-RANGE BEAM-BEAM EFFECT IN RHIC AND PLANS FOR COMPENSATION.

Description: At large distances the electromagnetic field of a wire is the same as the field produced by a bunch. Such a long-range beam-beam wire compensator was proposed for the LHC, and single beam tests with wire compensators were successfully done in the SPS. RHIC offers the possibility to test the compensation scheme with colliding beams. We report on measurements of beam losses as a function of transverse separation in RHIC at 100 GeV, and comparisons with simulations. We present a design for a long-range wire compensator in RHIC.
Date: June 23, 2006
Creator: FISCHER, W.; CALAGA, R.; DORDA, U.; DOUTCHOUK, J.-P.; ZIMMERMANN, F.; RANJBAR, V. et al.
Partner: UNT Libraries Government Documents Department

Parallel 3D Finite Element Particle-in-Cell Simulations with Pic3P

Description: SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic Particle-In-Cell code Pic3P. Designed for simulations of beam-cavity interactions dominated by space charge effects, Pic3P solves the complete set of Maxwell-Lorentz equations self-consistently and includes space-charge, retardation and boundary effects from first principles. Higher-order Finite Element methods with adaptive refinement on conformal unstructured meshes lead to highly efficient use of computational resources. Massively parallel processing with dynamic load balancing enables large-scale modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of next-generation accelerator facilities. Applications include the LCLS RF gun and the BNL polarized SRF gun.
Date: June 19, 2009
Creator: Candel, A.; Kabel, A.; Lee, L.; Li, Z.; Ng, C.; Schussman, G. et al.
Partner: UNT Libraries Government Documents Department

Parallel Higher-order Finite Element Method for Accurate Field Computations in Wakefield and PIC Simulations

Description: Over the past years, SLAC's Advanced Computations Department (ACD), under SciDAC sponsorship, has developed a suite of 3D (2D) parallel higher-order finite element (FE) codes, T3P (T2P) and Pic3P (Pic2P), aimed at accurate, large-scale simulation of wakefields and particle-field interactions in radio-frequency (RF) cavities of complex shape. The codes are built on the FE infrastructure that supports SLAC's frequency domain codes, Omega3P and S3P, to utilize conformal tetrahedral (triangular)meshes, higher-order basis functions and quadratic geometry approximation. For time integration, they adopt an unconditionally stable implicit scheme. Pic3P (Pic2P) extends T3P (T2P) to treat charged-particle dynamics self-consistently using the PIC (particle-in-cell) approach, the first such implementation on a conformal, unstructured grid using Whitney basis functions. Examples from applications to the International Linear Collider (ILC), Positron Electron Project-II (PEP-II), Linac Coherent Light Source (LCLS) and other accelerators will be presented to compare the accuracy and computational efficiency of these codes versus their counterparts using structured grids.
Date: June 19, 2009
Creator: Candel, A.; Kabel, A.; Lee, L.; Li, Z.; Limborg, C.; Ng, C. et al.
Partner: UNT Libraries Government Documents Department

Wakefield Computations for the CLIC PETS using the Parallel Finite Element Time-Domain Code T3P

Description: In recent years, SLAC's Advanced Computations Department (ACD) has developed the high-performance parallel 3D electromagnetic time-domain code, T3P, for simulations of wakefields and transients in complex accelerator structures. T3P is based on advanced higher-order Finite Element methods on unstructured grids with quadratic surface approximation. Optimized for large-scale parallel processing on leadership supercomputing facilities, T3P allows simulations of realistic 3D structures with unprecedented accuracy, aiding the design of the next generation of accelerator facilities. Applications to the Compact Linear Collider (CLIC) Power Extraction and Transfer Structure (PETS) are presented.
Date: June 19, 2009
Creator: Candel, A; Kabel, A.; Lee, L.; Li, Z.; Ng, C.; Schussman, G. et al.
Partner: UNT Libraries Government Documents Department

Wakefield Simulation of CLIC PETS Structure Using Parallel 3D Finite Element Time-Domain Solver T3P

Description: In recent years, SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic time-domain code T3P. Higher-order Finite Element methods on conformal unstructured meshes and massively parallel processing allow unprecedented simulation accuracy for wakefield computations and simulations of transient effects in realistic accelerator structures. Applications include simulation of wakefield damping in the Compact Linear Collider (CLIC) power extraction and transfer structure (PETS).
Date: June 19, 2009
Creator: Candel, A.; Kabel, A.; Lee, L.; Li, Z.; Ng, C.; Schussman, G. et al.
Partner: UNT Libraries Government Documents Department

Parallel Finite Element Particle-In-Cell Code for Simulations of Space-charge Dominated Beam-Cavity Interactions

Description: Over the past years, SLAC's Advanced Computations Department (ACD) has developed the parallel finite element (FE) particle-in-cell code Pic3P (Pic2P) for simulations of beam-cavity interactions dominated by space-charge effects. As opposed to standard space-charge dominated beam transport codes, which are based on the electrostatic approximation, Pic3P (Pic2P) includes space-charge, retardation and boundary effects as it self-consistently solves the complete set of Maxwell-Lorentz equations using higher-order FE methods on conformal meshes. Use of efficient, large-scale parallel processing allows for the modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of the next-generation of accelerator facilities. Applications to the Linac Coherent Light Source (LCLS) RF gun are presented.
Date: November 7, 2007
Creator: Candel, A. E.; Kabel, A. C.; Ko, Yong-kyu; Lee, L.; Li, Z.; Limborg-Deprey, C. et al.
Partner: UNT Libraries Government Documents Department

Observation of the Long-Range Beam-Beam Effect in RHIC and Plans for Compensation

Description: At large distances the electromagnetic field of a wire is the same as the field produced by a bunch. Such a longrange beam-beam wire compensator was proposed for the LHC, and single beam tests with wire compensators were successfully done in the SPS. RHIC offers the possibility to test the compensation scheme with colliding beams. We report on measurements of beam losses as a function of transverse separation in RHIC at 100GeV, and comparisons with simulations. We present a design for a long-range wire compensator in RHIC.
Date: June 18, 2007
Creator: Fischer, W.; Calaga, R.; /Brookhaven; Dorda, U.; Koutchouk, J.P.; Zimmermann, F. et al.
Partner: UNT Libraries Government Documents Department

SciDAC Advances in Beam Dynamics Simulation: From Light Sources to Colliders

Description: In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities (e.g., LCLS, RHIC, Tevatron, LHC, and ELIC). Particle accelerators are some of most important tools of scientific discovery. They are widely used in high-energy physics, nuclear physics, and other basic and applied sciences to study the interaction of elementary particles, to probe the internal structure of matter, and to generate high-brightness radiation for research in materials science, chemistry, biology, and other fields. Modern accelerators are complex and expensive devices that may be several kilometers long and may consist of thousands of beamline elements. An accelerator may transport trillions of charged particles that interact electromagnetically among themselves, that interact with fields produced by the accelerator components, and that interact with beam-induced fields. Large-scale beam dynamics simulations on massively parallel computers can help provide understanding of these complex physical phenomena, help minimize design cost, and help optimize machine operation. In this paper, we report on beam dynamics simulations in a variety of accelerators ranging from next generation light sources to high-energy ring colliders that have been studied during the first year of the SciDAC-2 accelerator project.
Date: November 14, 2011
Creator: Qiang, J.; Borland, M.; /LBL, Berkeley; Kabel, A.; /Argonne; Li, R. et al.
Partner: UNT Libraries Government Documents Department

Computational Science Research in Support of Petascale Electromagnetic Modeling

Description: Computational science research components were vital parts of the SciDAC-1 accelerator project and are continuing to play a critical role in newly-funded SciDAC-2 accelerator project, the Community Petascale Project for Accelerator Science and Simulation (ComPASS). Recent advances and achievements in the area of computational science research in support of petascale electromagnetic modeling for accelerator design analysis are presented, which include shape determination of superconducting RF cavities, mesh-based multilevel preconditioner in solving highly-indefinite linear systems, moving window using h- or p- refinement for time-domain short-range wakefield calculations, and improved scalable application I/O.
Date: June 20, 2008
Creator: Lee, L.-Q.; Akcelik, V; Ge, L; Chen, S; Schussman, G; Candel, A et al.
Partner: UNT Libraries Government Documents Department