摘要:

We survey the range of techniques for numerical simulation of the beam‐beam interaction in circular colliders in which synchrotron radiation is present. These include techniques used in weak‐strong, quasi‐strong‐strong, and strong‐strong simulations. Self‐consistent strong‐strong simulations usually use macroparticle‐in‐cell methods with a variety of refinements to increase the computational speed. Other approaches include macroparticle sampling methods and numerical solution of the Vlasov equation. We also describe and compare the existing beam‐beam simulation codes for circular lepton colliders. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1638371

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

In this paper, we present the results of using a parallel computational tool, BeamBeam3D, developed at Lawrence Berkeley National Laboratory, for strong‐strong/strong‐weak modeling of the beam‐beam effects in three hadron accelerators: RHIC, Tevatron and LHC. This tool calculates self‐consistently the electromagnetic beam‐beam forces for arbitrary distributions and separation during each collision when a strong‐strong beam‐beam interaction model is used. When a strong‐weak model is used, the code has the option of using a Gaussian approximation for the strong beam. Using the strong‐strong model, we have studied the effect of time modulated offset beam‐beam interaction on the emittance growth in the RHIC and LHC. We observed an extra 0.04&percent; emittance growth after 300,000 turns in the RHIC where the time‐averaged beam‐beam offset is one transverse rms beam size and the modulation frequency is 10 Hz. There is no significant additional emittance growth in the LHC after one million turns where the time‐averaged offset is zero. Using the strong‐weak model, we have also studied the antiproton lifetime subject to 72 long range beam‐beam interactions at 150 GeV injection energy in the Tevatron. The simulation shows a qualitative agreement with the experimental observation of the smaller antiproton emittance having a longer lifetime. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1638372

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We sketch the outlines of a perturbation scheme for the kick‐lattice map in two degrees of freedom (4‐d phase space) and apply it to the weak‐strong beam‐beam interaction. Our approach yields rigorous error bounds on the precision of our approximations (proofs will appear elsewhere), divides tune space into distinct regions where different approximations are valid, clarifies the dynamics near certain generically nonintegrable resonances, and generalizes to higher degrees of freedom and more complex models such as the strong‐strong beam‐beam. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1638373

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We developed a parallel code to calculate the evolution of the 4D phase space density of two colliding beams, which are coupled via the collective strong‐strong beam‐beam interaction, in the absence of diffusion and damping, using the Perron‐Frobenius (PF) operator technique. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1638374

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

One of the mechanisms of halo generation occurs when particles are trapped by a nonlinear resonancev≈m/pas the tunevis being modulated. This note is intended to renew some attention to this mechanism, and hopefully to trigger new study to understand it more quantitatively. This same mechanism used in reverse could serve to clean beam halos and to relax requirements on the collimators. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1638375

出版商:AIP    

年代:1903

数据来源: AIP