PAC07 - List of Keywords (collective-effects)

A B C D E F G H I K L M O P Q R S T U V W

collective-effects

Paper	Title	Other Keywords	Page
TUZBC02	SciDAC Frameworks and Solvers for Multi-physics Beam Dynamics Simulations	simulation, space-charge, optics, electron	894
	J. F. Amundson D. R. Dechow Tech-X, Boulder, Colorado J. Qiang, R. D. Ryne LBNL, Berkeley, California P. Spentzouris Fermilab, Batavia, Illinois
	The need for realistic accelerator simulations is greater than ever before due to the needs of design projects such as the ILC and optimization for existing machines. Sophisticated codes utilizing large-scale parallel computing have been developed to study collective beam effects such as space charge, electron cloud, beam-beam, etc. We will describe recent advances in the solvers for these effects and plans for enhancing them in the future. To date the codes have typically applied to a single collective effect and included just enough of the single-particle dynamics to support the collective effect at hand. We describe how we are developing a framework for realistic multi-physics simulations, i.e., simulations including the state-of-the-art calculations of all relevant physical processes.
	Slides

THPAN068	Wakefield Models for Particle Tracking Codes	multipole, simulation, dipole, quadrupole	3378
	A. Latina R. J. Barlow, A. Bungau UMAN, Manchester G. A. Blair Royal Holloway, University of London, Surrey G. Rumolo, D. Schulte CERN, Geneva J. D.A. Smith Lancaster University, Lancaster
	Wakefields have a considerable effect on beam dynamics and they must not be neglected for emittance growth studies, background estimates and other problems. The codes used for these problems are normally not capable of self-consistent wakefield calculations. They should thus be extended with either analytical models or export the wakefields numerically evaluated with other codes (such as Gdfidl) when analytical models are not feasible. We discuss both approaches and present their implementation in PLACET, MERLIN and BDSIM. The simulation results for the ILC and CLIC beam delivery systems are given as an example. Results produced with different codes are compared.

THPAN095	Implementation and Performance of Parallelized Elegant	simulation, space-charge, linac, damping	3444
	Y. Wang M. Borland ANL, Argonne, Illinois
	Funding: Work supported by the U. S. Department of Energy, Office of Science, Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The program Elegant* is widely used for design and modeling of linacs for free-electron lasers and energy recovery linacs, as well as storage rings and other applications. As part of a multi-year effort, we have parallelized many aspects of the code, including single-particle dynamics, wakefields, and coherent synchrotron radiation. We report on the approach used for gradual parallelization, which proved very beneficial in getting parallel features into the hands of users quickly. We also report details of parallelization of collective effects. Finally, we discuss performance of the parallelized code in various applications. *M. Borland, APS Light Source Note LS-287, September 2000.

THPAS085	Kinetic Equilibrium and Stability Properties of 3D High-Intensity Charged Particle Bunches	simulation, coupling, transverse-dynamics, plasma	3681
	H. Qin R. C. Davidson, E. Startsev PPPL, Princeton, New Jersey
	Funding: Research supported by the U. S. Department of Energy. In 3D high-intensity bunched beams, the collective effects associated with strong coupling between the longitudinal and transverse dynamics are of fundamental importance. A direct consequence of this coupling is that the particle dynamics does not conserve transverse energy and longitudinal energy separately, and there exists no exact kinetic equilibrium which has an anisotropic energy in the transverse and longitudinal directions. The strong coupling also introduces a mechanism for the electrostatic Harris-type instability driven by strong temperature anisotropy, which exists naturally in beams that have been accelerated to large velocities. The self-consistent Vlasov-Maxwell equations are applied to high-intensity bunched beams, and a generalized low-noise delta-f particle simulation algorithm is developed for bunched beams with or without energy anisotropy. Systematic studies are carried out that determine the particle dynamics, the approximate equilibrium, and stability properties under conditions corresponding to strong 3D nonlinear space-charge force. Finite bunch-length effects on collective excitations and anisotropy-driven instabilities are also investigated.

FRPMN099	Equilibrium Fluctuations in an N-Particle Coasting Beam: Schottky Noise Effects	impedance, plasma, vacuum, longitudinal-dynamics	4318
	G. Bassi J. A. Ellison, K. A. Heinemann UNM, Albuquerque, New Mexico
	Funding: Supported by DOE grant DE-FG02-99ER41104 We discuss the longitudinal dynamics of an unbunched beam with a collective effect due to the vacuum chamber and with the discretness of an N-particle beam (Schottky noise) included. We start with the 2N equations of motion (in angle and energy) with random initial conditions. The 2D phase space density for the N-Particles is a sum of delta functions and satisfies the Klimontovich equation. An arbitrary function of the energy also satisfies the Klimontovich equation and we linearize about a convenient equilibrium density taking the initial conditions to be independent, identically distributed random vaiables with the equilibrium distribution. The linearized equations can be solved using a Laplace transform in time and a Fourier series in angle. The resultant stochastic process for the phase space density is analyzed and compared with a known result. Work is in progress to study the full nonlinear problem. To gain further insight we are studying three alternative approaches: (1) a BBGKY approach, (2) an approach due to Elskens and Escande* and (3) the 'three-level-approach' of Donsker and Varadhan (see "Entropy, Large Deviations and Statistical Mechanics'', by R. S. Ellis). * V. V. Parkhomchuk and D. V. Pestrikov, Sov. Phys. Tech. Phys. 25(7), July 1980 ** "Microscopic Dynamics of Plasmas and Chaos", Y. Elskens and D. Escande, IoP, Series in Plasma Physics, 2003.