Multiparticle Beam Dynamics


Paper Title Page
TPAP056 Electron Beam Stability Requirements for Linac-Ring Electron-Ion Colliders 3363
  • C. Montag
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

In recent years, linac-ring electron-ion colliders have been proposed at a number of laboratories around the world. While the linac-ring approach overcomes the beam-beam tuneshift limitation on the electron beam, it also introduces noise into the ion beam, via the beam-beam interaction with electron bunches of slightly fluctuating intensity and transverse size. The effect of these fluctuations is studied using a linearized model of the beam-beam interaction. Upper limits for the rms jitter amplitudes of electron beam parameters for various linac-ring electron-ion colliders are presented.

TPAT005 Start to End Error Study for the SPIRAL2 Linac 934
  • R. Duperrier, D. Uriot
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  Funding: CEA

The possibility of a high intensity accelerator at GANIL, producing secondary beams of unprecedented intensity, is considered. The proposed driver for the SPIRAL2 project aims to accelerate a 5 mA deuteron beam up to 20 A.MeV and a 1 mA ion beam for q/A = 1/3 up to 14.5 A.MeV. It is a continuous wave regime linac, designed for a maximum efficiency in the transmission of intense beams and a tunable energy. This paper presents the error sensitivity study which has been performed for this linac in order to define the tolerances for the construction. The correction scheme and the expected losses are described.

TPAT006 Impact of Optics on CSR-Related Emittance Growth in Bunch Compressor Chicanes 1015
  • T. Limberg, M. Dohlus
    DESY, Hamburg
  The dependence of emittance growth due to Coherent Synchrotron Radiation (CSR) in bunch compressor chicanes on optics has been noticed and empirically studied in the past. We revisit the subject, suggesting a model to explain slice emittance growth dependence on chicane optics. A simplified model to calculate projected emittance growth when it is mainly caused by transverse slice centroid offsets is presented. It is then used to find optimal compensation of centroid kicks in the single chicanes of a two-stage compression system by adjusting the phase advance of the transport in between and the ration of the compression factors.  
TPAT007 RF Defocusing in Super-Conducting Structure with Constant Geometry 1042
  • Y. Senichev, R. Maier, N.E. Vasyukhin
    FZJ, Jülich
  Due to higher accelerating gradient in the super-conducting linac the RF defocusing factor plays significant role in the beam dynamics. Together with the space charge it is a main reason for the stability loss. Usually it is estimated in frame of the travelling wave formalism with synchronous motion. However, the super-conducting cavity is desirable to have the constant geometry, when synchronous motion is absent. In this case the quasi-synchronous phase velocity is adjusted by RF phasing. In this paper we investigate RF defocusing factor in absent of synchronism between the beam and the accelerating structure.  
TPAT008 Numerical Dispersion Error Reduction in EM Calculations for Accelerators 1114
  • T. Lau, E. Gjonaj, T. Weiland
    TEMF, Darmstadt
  • I. Zagorodnov
    DESY, Hamburg
  Funding: Deutsches Elektronen-Synchrotron DESY

In this contribution novel numerical algorithms with no dispersion along the beam axis are investigated. This property is of interest for the long-time calculation of electromagnetic fields in accelerators. Instead of increasing the spatial stencil of the Yee scheme the compared methods modify the time-stepping algorithm.The results are compared on several test examples. As a practical application the electromagnetic field of a very short bunch inside a cavity is calculated.

TPAT010 Practical Definitions of Beam Lifetimes in an Electron Storage Ring 1216
  • T.-Y. Lee
    PAL, Pohang, Kyungbuk
  Derived are simple definitions of beam lifetimes in an electron storage ring. They are defined in terms of measured beam lifetime and its time derivative. They are practical rather than theoretical. The only condition required is suppression or saturation of the radiative polarization.  
TPAT011 Impedance Analysis of Longitudinal Bunch Shape Measurements at PLS
  • I. Hwang, M. Yoon
    POSTECH, Pohang, Kyungbuk
  • Y.J. Han, E.-S. Kim
    PAL, Pohang, Kyungbuk
  We measured the longitudinal bunch shape by streak camera at 2.5 GeV Pohang Light Source. The impedances estimated by a series R+L model indicate a resistance R= 960 ohm, an inductance L= 80 nH and a longitudinal impedance Z/n= 0.53 ohm. The scaling law for the bunch lengthenig is expressed as I0.22. The effects of insertion device in the ring on the ring impedance, particularly the vertical height of in-vacuum undulator are also presented.  
TPAT014 A Novel Technique for Multiturn Injection in a Circular Accelerator Using Stable Islands in Transverse Phase Space 1377
  • M. Giovannozzi, J. Morel
    CERN, Geneva
  By applying a time-reversal to the multiturn extraction recently proposed a novel approach to perform multiturn injection is proposed. It is based on the use of stable islands of the horizontal phase space generated by means of sextupoles and octupoles. A particle beam can be injected into stable islands of phase space, and then a slow tune variation allows merging the beam trapped inside the islands. The results of numerical simulations will be presented and discussed in details, showing how to use the proposed approach to generate hollow bunches.  
TPAT015 Simulations of Error-Induced Beam Degradation in Fermilab's Booster Synchrotron 1458
  • P.S. Yoon
    Rochester University, Rochester, New York
  • C.L. Bohn
    Northern Illinois University, DeKalb, Illinois
  • W. Chou
    Fermilab, Batavia, Illinois
  Funding: Work supported by the University Research Association, Inc. under U.S. Department of Energy (DOE) contract No. DE-AC02-76-CH03000, and by DOE grant No. DE-FG02-04ER41323 to NIU, and by DOE grant No. DE-FG02-91ER40685 to University of Rochester.

Individual particle orbits in a beam will respond to both external focusing and accelerating forces as well as internal space-charge forces. The external forces will reflect unavoidable systematic and random machine errors, or imperfections, such as jitter in magnet and radio-frequency power supplies, as well as magnet translation and rotation alignment errors. The beam responds in a self-consistent fashion to these errors; they continually do work on the beam and thereby act as a constant source of energy input. Consequently, halo formation and emittnace growth can be induced, resulting in beam degradation and loss. We have upgraded the ORBIT-FNAL package and used it to compute effects of machine errors on emittance dilution and halo formation in the existing FNAL-Booster synchrotron. This package can be applied to study other synchrotrons and storage rings, as well.

TPAT017 Transverse Impedance of Elliptical Tapers 1535
  • B. Podobedov, S. Krinsky
    BNL, Upton, Long Island, New York
  Funding: Work supported by the U.S. DOE.

The geometric impedance of small-gap undulator chambers is of paramount importance for modern light sources because it may drive transverse single bunch instabilities. Analytical expressions are derived for the transverse impedance assuming a slowly tapered vacuum chamber with a confocal elliptical cross-section. The analytical results are confirmed by numerical simulations with the GdfidL Electromagnetic Field simulator and they yield the correct asymptotic limits for both round and flat chambers.

TPAT018 Stability of Barrier Buckets with Short or Zero Barrier Separations 1589
  • K.Y. Ng
    Fermilab, Batavia, Illinois
  A barrier bucket with small separation between the rf barriers (relative to the barrier widths) or even zero separation has its synchrotron tune decreasing rather slowly towards the boundary of the bucket. As a result, large area at the bucket edges can become unstable under the modulation of rf voltage and rf phase. Application is made to those barrier buckets used in the process of momentum mining on the issues of bunch-distribution distortion and particle loss.  
TPAT019 Discussions on the Cancellation Effect on a Curved Orbit 1631
  • R. Li, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  Funding: Work supported by DOE Contract DE-AC05-84ER40150.

The canonical formulation and the cancellation effect for bunch dynamics under collective interaction on a curved orbit were presented in Ref. [*]. Some possible controversial representations of the cancellation effect were later addressed by Geloni et al.** In this study, we discuss all the points raised in Ref. [**] based on our canonical treatment, and show how these points can be perceived from the view point of the cancellation picture.

*R. Li and Ya. S. Derbenev, Jefferson Laboratory Report No. LJAB-TN-02-054, 2003. **G. Geloni et al., DESY Report No. DESY 03-165, 2003.

TPAT022 Future Plans for the Small Isochronous Ring 1778
  • E.P. Pozdeyev
    Jefferson Lab, Newport News, Virginia
  • F. Marti, R.C. York
    NSCL, East Lansing, Michigan
  • J.A. Rodriguez
    CERN, Geneva
  Funding: Work supported by NSF Grant #PHY-0110253 and DOE Contract DE-AC05-84ER40150.

The Small Isochronous Ring has been operational at Michigan State University since December 2003. It is used for experimental studies of the beam dynamics in high-intensity isochronous cyclotrons and synchrotrons at the transition energy. The operational experience with SIR has proven that the ring can be successfully used to study space charge effects in accelerators. The low velocity of beam particles in the ring allowed us to achieve a high accuracy of longitudinal profile measurements that is difficult to achieve in full-size accelerators. The experimental data obtained in the ring was used for validation of multi-particle, space-charge codes CYCO and WARP3D. Inspired by the solid performance of SIR in the isochronous regime, we consider options for expanding the scope of the beam physics studied in the ring. In this paper, we outline possible future experiments and discuss required modifications of the ring optics and hardware.

TPAT023 Tests of a 3D Self Magnetic Field Solver in the Finite Element Gun Code MICHELLE 1814
  • E.M. Nelson
    LANL, Los Alamos, New Mexico
  • J.J. Petillo
    SAIC, Burlington, Massachusetts
  Funding: Work supported by ONR.

We have recently implemented a prototype 3d self magnetic field solver in the finite-element gun code MICHELLE. The new solver computes the magnetic vector potential on unstructured grids. The solver employs edge basis functions in the curl-curl formulation of the finite-element method. A novel current accumulation algorithm takes advantage of the unstructured grid particle tracker to produce a compatible source vector, for which the singular matrix equation is easily solved by the conjugate gradient method. We will present some test cases demonstrating the capabilities of the prototype 3d self magnetic field solver. One test case is self magnetic field in a square drift tube. Another is a relativistic axisymmetric beam freely expanding in a round pipe.

TPAT026 Synergia: An Advanced Object-Oriented Framework for Beam Dynamics Simultation 1925
  • D.R. Dechow, P. Stoltz
    Tech-X, Boulder, Colorado
  • J.F. Amundson, P. Spentzouris
    Fermilab, Batavia, Illinois
  Synergia is a 3-D, parallel, particle-in-cell beam dynamics simulation toolkit. At heart of the software development effort is the integration of two extant object-oriented accelerator modeling frameworks–Impact written in Fortran 90 and mxyptlk written in C++–so that they may be steered by a third, a more flexible human interface framework, written in Python. Recent efforts are focused on the refactoring of the Impact-Fortran 90 codes in order to expose more loosely-coupled interfaces to the Python interface framework.  
TPAT027 Measurement of Transverse Echoes in RHIC 1955
  • W. Fischer, T. Satogata
    BNL, Upton, Long Island, New York
  • R. Tomas
    CELLS, Bellaterra (Cerdanyola del Vallès)
  Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886.

Beam echoes are a very sensitive method to measure diffusion, and longitudinal echo measurements were performed in a number of machines. In RHIC, for the first time, a transverse beam echo was observed after applying a dipole kick followed by a quadrupole kick. After application of the dipole kick, the dipole moment decohered completely due to lattice nonlinearities. When a quadrupole kick is applied at time T after the dipole kick, the beam re-cohered at time 2T thus showing an echo response. We describe the experimental setup and measurement results. In the measurements the dipole and quadrupole kick amplitudes, amplitude dependent tune shift, and the time between dipole and quadrupole kick were varied. In addition, measurements were taken with gold bunches of different intensities. These should exhibit different transverse diffusion rates due to intra-beam scattering.

TPAT028 TRACK: The New Beam Dynamics Code 2053
  • B. Mustapha, V.N. Aseev, E.S. Lessner, P.N. Ostroumov
    ANL, Argonne, Illinois
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38.

The new ray-tracing code TRACK was developed* to fulfill the special requirements of the RIA accelerator systems. The RIA lattice includes an ECR ion source, a LEBT containing a MHB and a RFQ followed by three SC linac sections separated by two stripping stations with appropriate magnetic transport systems. No available beam dynamics code meet all the necessary requirements for an end-to-end simulation of the RIA driver linac. The latest version of TRACK was used for end-to-end simulations of the RIA driver including errors and beam loss analysis.** In addition to the standard capabilities, the code includes the following new features: i) multiple charge states ii) realistic stripper model; ii) static and dynamic errors iii) automatic steering to correct for misalignments iv) detailed beam-loss analysis; v) parallel computing to perform large scale simulations. Although primarily developed for simulations of the RIA machine, TRACK is a general beam dynamics code. Currently it is being used for the design and simulation of future proton and heavy-ion linacs at TRIUMF, Fermilab, JLAB and LBL.

*P.N. Ostroumov and K.W. Shepard. Phys. Rev. ST. Accel. Beams 11, 030101 (2001). **P.N. Ostroumov, V. N. Aseev, B. Mustapha. Phys. Rev. ST. Accel. Beams, Volume 7, 090101 (2004).

TPAT029 RIA Beam Dynamics: Comparing TRACK to IMPACT 2095
  • B. Mustapha, V.N. Aseev, P.N. Ostroumov
    ANL, Argonne, Illinois
  • J. Qiang, R.D. Ryne
    LBNL, Berkeley, California
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38.

In order to benchmark the newly developed beam dynamics code TRACK we have performed comparisons with well established existing codes. During code development, codes like TRANSPORT, COSY, GIOS and RAYTRACE were used to check TRACK's implementation of the different beam line elements. To benchmark the end-to-end simulation of the RIA driver linac, the simulation of the low-energy part (from the ion source to the entrance of the SC linac) was compared with PARMTEQ and found to agree well. For the simulation of the SC linac the code IMPACT is used. Prior to these simulations, the code IMPACT had to be updated to meet the special requirements of the RIA driver linac. Features such as multiple charge state acceleration, stripper simulation and beam collimation were added to the code. IMPACT was also modified to support new types of rf cavities and to include fringe fields for all the elements. This paper will present a comparison of the beam dynamics simulation in the RIA driver linac between the codes TRACK and IMPACT. A very good agreement was obtained which represents another validation of both codes.

TPAT030 Transverse Beam Matching Application for SNS 2143
  • C. Chu, V.V. Danilov, D.-O. Jeon, M.A. Plum
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

An automated transverse beam matching application has been developed for the Spallation Neutron Source (SNS) beam transport lines. The application is written within the XAL Java framework and the matching algorithm is based on the simplex optimization method. Other functionalities, such as emittance calculated from profile monitor measurements (adopted from a LANL Fortran code), profile monitor display, and XAL on-line model calculation, are also provided by the application. Test results obtained during the SNS warm linac commissioning will be reported. A comparison between the emittances obtained from this application and an independent Trace-3D routine will also be shown.

TPAT031 Painting Self-Consistent Beam Distributions in Rings 2194
  • J.A. Holmes, S.M. Cousineau, V.V. Danilov
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

We define self-consistent beam distributions to have the following properties: 1) time-independence or periodicity, 2) linear space charge forces, and 3) maintainance of their defining shape and density under all linear transformations. The periodic condition guarantees zero space-charge-induced halo growth and beam loss during injection. Some self-consistent distributions can be manipulated into flat, or even point-like, beams, which makes them interesting to colliders and to heavy-ion fusion. This paper presents methods for painting 2D and 3D self-consistent distributions and for their manipulation to produce flat and point-like beams.

TPAT032 Transverse Stability Studies of the SNS Ring 2254
  • J.A. Holmes, V.V. Danilov
    ORNL, Oak Ridge, Tennessee
  • L.K. Jain
    UW/Physics, Waterloo, Ontario
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

Detailed studies of the transverse stability of the SNS ring have been carried out for realistic injection scenarios. For coasting beam models and single harmonic impedances, analytic and computational results including phase slip, chromaticity, and space charge are in excellent agreement. For the dominant extraction kicker impedance and bunched beams resulting from injection, computationally determined stability thresholds are significantly higher than for coasting beams. At this time, we have no analytic model to treat the bunched beam case, but we present a formulation that provides an approach to this problem.

TPAT033 Experimental Characterizations of 4-D Transverse Phase-Space of a Compressed Beam 2263
  • F. Zhou, R.B. Agustsson, G. Andonian, D. Cline, A.Y. Murokh, J.B. Rosenzweig
    UCLA, Los Angeles, California
  • I. Ben-Zvi, V. Yakimenko
    BNL, Upton, Long Island, New York
  Funding: Work supported by U.S. DOE.

Coherent synchrotron radiation can significantly distort beam phase spaces in longitudinal direction and bending plane through a bunch compressor. A tomography technique is used to reconstruct transverse phase space of electron beam. Transverse 4-D phase spaces are systematically measured at UCLA/ATF compressor and their characteristics with different bunch compression conditions are analyzed.

TPAT034 Manipulations of Double Electron Beams within One RF Period for Seeded SM-LWFA Experiment 2312
  • F. Zhou, D. Cline
    UCLA, Los Angeles, California
  • M. Babzien, V. Yakimenko
    BNL, Upton, Long Island, New York
  • W.D. Kimura
    STI, Washington
  Funding: Work supported by U.S. DOE.

Although seeded SM-LWFA only requires one electron beam to initiate the laser wakefield, it would be highly desirable to have a second electron beam traveling after the first one to probe the accelerated electrons. To create and preserve significant amount of wakefield in the STELLA SM-LWFA experiment, the first e-beam needs to be tiny (<40 microns FWHM) in size and short in length within the plasma. To probe the wakefield which is damped within 10 ps for certain plasma density, the separation between the first and second beams needs to be within one RF period and the second e-beam must have smaller energy spread and smaller size. Design of double beams in one RF period to meet the strict requirements and the preliminary beam study at BNL-ATF facility are presented. The scheme of double beams with ATF bunch compressor is also discussed.

TPAT035 Coherent Synchrotron Radiation from an Electron Beam in a Curved Waveguide 2390
  • D.R. Gillingham, T. M. Antonsen, P.G. O'Shea
    IREAP, College Park, Maryland
  Funding: Research supported by the office of Naval Research and the Joint Technology Office.

The radiation emitted by a pulsed electron beam as it travels on a circular trajectory inside a waveguide is calculated using a 3D simulation. Forward-propagating wave equations for the fields in the waveguide are calculated by a perturbation of the Maxwell equations where the radius of curvature is large compared to the dimensions of the waveguide. These are integrated self-consistently with the distribution of charge in the beam to provide the complete fields (electric and magnetic) for all times during the passage of the beam through the waveguide and therefore are applicable to sections of any length or combinations thereof. The distribution of electrons and their momentum are also modified self-consistently so that the results may be used to estimate the effect of the radiation on the beam quality (emittance and energy spread).

TPAT036 Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization 2452
  • P. Efthimion, R.C. Davidson, E.P. Gilson, L. Grisham
    PPPL, Princeton, New Jersey
  • B. G. Logan, W. Waldron, S. Yu
    LBNL, Berkeley, California
  Funding: Research supported by the U.S. Department of Energy.

Plasmas are employed as a medium for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ~ 0.1-1 m would be suitable. To produce 1 meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic. High voltage (~ 1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long produced plasma densities ~ 5x1011 cm-3. The source was integrated into the experiment and successfully charge neutralized the K ion beam. Presently, the 1 meter source is being fabricated. It will be characterized and integrated into NDCX for charge neutralization experiments. Experimental results will be presented.

TPAT037 Simulating the Long-Distance Propagation of Intense Beams in the Paul Trap Simulator Experiment 2491
  • E.P. Gilson, M. Chung, R.C. Davidson, P. Efthimion, R. M. Majeski, E. Startsev
    PPPL, Princeton, New Jersey
  Funding: Research supported by the U.S. Department of Energy.

The Paul Trap Simulator Experiment (PTSX) makes use of a compact Paul trap configuration with quadrupolar oscillating wall voltages to simulate the propagation of intense charged particle beams over distances of many kilometers through magnetic alternating-gradient transport systems. The simulation is possible because of the similarity between the transverse dynamics of particles in the two systems. One-component pure cesium ion plasmas have been trapped that correspond to normalized intensity parameters s < 0.8, where s is the ratio of the square of the plasma frequency to twice the square of the average transverse focusing frequency. The PTSX device confines the plasma for hundreds of milliseconds, which is equivalent to beam propagation over tens of kilometers. Results are presented for experiments in which the amplitude of the oscillating confining voltage waveform has been modified as a function of time. A comparison is made between abrupt changes in amplitude and adiabatic changes in amplitude. The effects of varying the frequency are also discussed. A barium ion source and a laser system have been installed and initial measurements made with this system are presented.

TPAT038 Chaos in Time-Dependent Space-Charge Potentials 2515
  • G.T. Betzel, C.L. Bohn, I.V. Sideris
    Northern Illinois University, DeKalb, Illinois
  We consider a spherically symmetric, homologously breathing, space-charge-dominated beam bunch in the spirit of the particle-core model. The question we ask is: How does the time dependence influence the population of chaotic orbits? The static beam has zero chaotic orbits; the equation of particle motion is integrable up to quadrature. This is generally not true once the bunch is set into oscillation. We quantify the population of chaotic orbits as a function of space charge and oscillation amplitude (mismatch). We also apply a newly developed measure of chaos, one that distinguishes between regular, sticky, and wildly chaotic orbits, to characterize the phase space in detail. We then introduce colored noise into the system and show how its presence modifies the dynamics. One finding is that, despite the presence of a sizeable population of chaotic orbits, halo formation in the homologously breathing beam is much less prevalent than in an envelope-matched counterpart wherein an internal collective mode is excited.  
TPAT039 Wavelet-Based Poisson Solver for Use in Particle-in-Cell Simulations 2601
  • B. Terzic, C.L. Bohn, D. Mihalcea
    Northern Illinois University, DeKalb, Illinois
  • I.V. Pogorelov
    LBNL, Berkeley, California
  Funding: Work of B.T., D.M. and C.L.B. is supported by Air Force contract FA9471-040C-0199. Work of I.V.P. is supported by the U.S. Department of Energy contract DE-AC03-76SF00098.

We report on a successful implementation of a wavelet-based Poisson solver for use in 3D particle-in-cell simulations. One new aspect of our algorithm is its ability to treat the general (inhomogeneous) Dirichlet boundary conditions. The solver harnesses advantages afforded by the wavelet formulation, such as sparsity of operators and data sets, existence of effective preconditioners, and the ability simultaneously to remove numerical noise and further compress relevant data sets. Having tested our method as a stand-alone solver on two model problems, we merged it into IMPACT-T to obtain a fully functional serial PIC code. We present and discuss preliminary results of application of the new code to the modelling of the Fermilab/NICADD and AES/JLab photoinjectors.

Corresponding author: B.T. (

TPAT040 Actual Stationary State for Plasma Lens 2619
  • V. Zadorozhny
    NASU/IOC, Kiev
  • A. Goncharov
    NSC/KIPT, Kharkov
  • Z.P. Parsa
    BNL, Upton, Long Island, New York
  The electrostatic plasma lens (PL) provides an attractive and unique tool for manipulating high-current heavy ion beams. The fundamental concept of the PL is based on the use of magnetically insulated electrons and equipotentialization of magnetic field lines. Rigorous application of PL is, however, limited. The reason is the estimation behaviour of electrons for complicated magnetic fields runs into severe difficults.We show that there are specific conditions that admit steady-state of a longitudinal motion, and consider a question of it stability. These results are needed to develop an optimized PL with minimal spherical aberation, in party by optimization of the magnetic field conficuration in the low-magnetic-field range.  
TPAT041 On the Vlasov-Maxwell Equations 2654
  • V. Zadorozhny
    NASU/IOC, Kiev
  • Z.P. Parsa
    BNL, Upton, Long Island, New York
  There are many interesting physical question which based on of the solution Vlasov-Maxwell Equation (VME). However, the procedure of solve is very difficult and hard. But it is often preferable, on physical grounds, to a common point of view. Such point of view maybe a structure of some solution. We define and discuss the notaion of structure for the distribution function and prove, the structure of the Lorentz force represent the structure of the one. At the time of the discovery of the integrable systems the question of VME integrability had been considered. Moreover, as example, we consider, by means of this approach, the relation integrability and dispersion with a spectra of Vlasov's operat.  
TPAT042 Progress on a Vlasov Treatment of Coherent Synchrotron Radiation from Arbitrary Planar Orbits 2699
  • G. Bassi, J.A. Ellison
    UNM, Albuquerque, New Mexico
  • R.L. Warnock
    SLAC, Menlo Park, California
  Funding: Support from DOE grants DE-AC02-76SF00515 and DE-FG02-99ER1104 is gratefully acknowledged.

We study the influence of coherent synchrotron radiation (CSR) on particle bunches traveling on arbitrary planar orbits between parallel conducting plates (shielding). The time evolution of the phase space distribution is determined by solving the Vlasov-Maxwell equations in the time domain. This provides lower numerical noise than the macroparticle method, and allows the study of emittance degradation and microbunching in bunch compressors. We calculate the fields excited by the bunch in the lab frame using a formula simpler than that based on retarded potentials.* We have developed an algorithm for solving the Vlasov equation in the beam frame using arc length as the independent variable and our method of local characteristics (discretized Perron-Frobenius operator).We integrate in the interaction picture in the hope that we can adopt a fixed grid. The distribution function will be represented by B-splines, in a scheme preserving positivity and normalization of the distribution. The transformation between lab and beam frame is carefully treated. Here we report on our implementation of the algorithm for a chicane bunch compressor with linear energy chirp and take steps to treat the nonlinear case.

*"Vlasov Treatment of Coherent Synchrotron Radiation from Arbitrary Planar Orbits" to be published in the Proceedings of ICAP04, St. Petersburg, R. Warnock, G. Bassi and J. A. Ellison.

TPAT043 The MICHELLE 2D/3D ES PIC Code: Advances and Applications
  • J.J. Petillo, N.J. Dionne, K. Eppley, J. N. P. Panagos, X. Z. Zhai
    SAIC, Burlington, Massachusetts
  • L. C. Chernyakova, J.F. DeFord, B. H. Held
    STAR, Inc., Mequon, Wisconsin
  • B. Levush
    NRL, Washington, DC
  • E.M. Nelson
    LANL, Los Alamos, New Mexico
  Funding: Office of Naval Research, Naval Research Laboratory.

MICHELLE is a new 2D/3D steady-state and time-domain particle-in-cell (PIC) code* that employs electrostatic and now magnetostatic finite-element field solvers. The code has been used to design and analyze a wide variety of devices that includes multistage depressed collectors, gridded guns, multibeam guns, annular-beam guns, sheet-beam guns, beam-transport sections, and ion thrusters. Latest additions to the MICHELLE/Voyager tool are as follows: 1) a prototype 3D self magnetic field solver using the curl-curl finite-element formulation for the magnetic vector potential, employing edge basis functions and accumulating current with MICHELLE's new unstructured grid particle tracker, 2) the electrostatic field solver now accommodates dielectric media, 3) periodic boundary conditions are now functional on all grids, not just structured grids, 4) the addition of a global optimization module to the user interface where both electrical parameters (such as electrode voltages)can be optimized, and 5) adaptive mesh refinement improvements. Applications illustrating these latest additions will be presented, including a relativistic sheet beam gun, a relativistic MIG gun, and a depressed collector optimization example.

*John Petillo, et al., IEEE Trans. Plasma Sci., vol. 30, no. 3, June 2002, pp. 1238-1264.

TPAT072 Long-Term Simulation of Beam-Beam Effects in the Tevatron at Collision Energy 3871
  • A.C. Kabel, Y. Cai
    SLAC, Menlo Park, California
  • T. Sen
    Fermilab, Batavia, Illinois
  The weak-strong beam-beam effect is expected substantially to contribute to the degradation of beam lifetimes in the Tevatron at collision energy. We have expanded an existing multi-processor code (which previously was applied to the Tevatron at injection energy* to include chromatic and non-linear lattice effects as well as a fully-coupled treatment of the lattice in different approximations.** We obtain lifetime predictions by doing temporal statistics on the tracking results of a weighted macroparticle distribution and fitting it to a class of solutions for the diffusion equation. We present typical results of parameter scans.

*A. Kabel, Y. Cai, B. Erdelyi, T. Sen, M. Xiao; Proceedings of PAC03. **A. Kabel, this Conference.