Keyword: beam-beam-effects
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MOPME027 Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders simulation, collider, linear-collider, positron 439
 
  • M.A. Boronina, V.D. Korneev, V.A. Vshivkov
    ICM&MG SB RAS, Novosibirsk, Russia
 
  We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME027  
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TUPRO023 Beam-beam Effects in Different Luminosity Levelling Scenarios for the LHC luminosity, dynamic-aperture, experiment, emittance 1061
 
  • X. Buffat, D. Banfi, G.R. Coombs
    EPFL, Lausanne, Switzerland
  • W. Herr, T. Pieloni
    CERN, Geneva, Switzerland
 
  Adjusting luminosity and optimizing the luminous region in each interaction point of the LHC according to the experiments needs has become a requirement to maximize the efficiency of the different detectors. Several techniques are envisaged, most importantly by varying β* or a transverse offset at the interaction point. Coherent and incoherent stability in the presence of beam-beam effects will be discussed in realistic luminosity levelling scenarios for the LHC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO023  
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THPRO060 Beam-beam Effect on the BTF in Bunched Beams electron, simulation, damping, operation 3011
 
  • P.A. Görgen, O. Boine-Frankenheim
    TEMF, TU Darmstadt, Darmstadt, Germany
  • W. Fischer
    BNL, Upton, Long Island, New York, USA
 
  We present studies on the transverse baseband Beam Transfer Functions (BTFs) in bunched beams at high energies. The goal of the work is to evaluate whether transverse BTFs can be used to diagnose the tune spread arising from transverse nonlinearities such as the beam-beam effect and space charge. We employ an analytic expression to the BTFs of beams under a transverse nonlinear lens arising from a bi-Gaussian charge distribution. We obtain agreement between a simulation model of an electron-lens like configuration and the analytic results. The tune spread for this scenario can be recovered by means of a fit against the analytic expectation. The results are compared with measurements where the beam-beam effect acts as a substitute for the electron lens. A similar behaviour of the BTF is observed. This allows the conclusion that the transverse BTF can be used to diagnose tune spread from an electron-lens. Finally we discuss the problems that arise when trying to recover the tune spread from BTFs of arbitrary non-Gaussian beams and in the presence of coherent beam-beam modes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO060  
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THPRO083 Weak-strong Beam-beam Simulations for HL-LHC optics, simulation, luminosity, dynamic-aperture 3079
 
  • D. Banfi, J. Barranco García
    EPFL, Lausanne, Switzerland
  • T. Pieloni
    CERN, Geneva, Switzerland
  • A. Valishev
    Fermilab, Batavia, Illinois, USA
 
  In this paper we present dynamic aperture studies for possible High Luminosity LHC optics in the presence of beam-beam interactions, crab crossing schemes and magnets multipolar errors. Possible operational scenarios of luminosity leveling by transverse offset and betatron function are also studied and the impact on the beams stability is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO083  
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THPRI006 Dynamic Aperture Study of SuperKEKB with Beam-beam Effect dynamic-aperture, sextupole, quadrupole, lattice 3773
 
  • A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto
    KEK, Ibaraki, Japan
 
  The SuperKEKB is an asymmetric-energy double-ring collider to achieve 40 times higher luminosity than that of the KEKB B-factory. The strong non-linearity of both final focusing and beam-beam force, which are required to achieve such high luminosity, reduce dynamic aperture and limit Touschek beam lifetime. In order to achieve long enough beam lifetime for collision operation, we are studying the dynamic aperture under beam-beam effect. The study results of both dynamic aperture and Touschek beam lifetime are reported in this presentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI006  
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