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coupling

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TUMPMP02 Magnetodynamic Formulation Resolving Eddy-Current Effects in the Yoke and the Superconductive Cable of the FAIR Dipole Magnets superconductivity, dipole, simulation, synchrotron 90
 
  • H. De Gersem, S. Koch, T. Weiland
    TEMF, Darmstadt
  Funding: This work was supported by the Gesellschaft für Schwerionenforschung (GSI), Darmstadt.

Transient 3D simulations are carried out for two types of superconductive dipole magnets. Eddy-current effects in the yoke are treated by homogenising the laminated iron composite whereas interstrand eddy-current effects are resolved by either a cable magnetization model or a cable eddy-current model. The simulations reveal the Joule losses in the magnets.

 
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TUPPP24 Transverse Coupling Impedance of a Ferrite Kicker Magnet: Comparison between Simulations and Measurements impedance, kicker, simulation, electromagnetic-fields 128
 
  • E. Arevalo, B. Doliwa, T. Weiland
    TEMF, Darmstadt
  Funding: This work was partially funded by DIRACsecondary-Beams(RIDS-515873).

The driving terms of instabilities in particle accelerators depend on the beam surroundings which are conveniently described by coupling impedances. In the case of critical components, for which analytical calculations are not available, direct measurements of the coupling impedances on a prototype are usually needed. However, this obvious drawback on the design of particle accelerators can be overcome by electromagnetic field simulations within the framework of the Finite Integration Technique. Here we show results from numerical evaluations of the transverse coupling impedance of a ferrite kicker. In order to excite the electromagnetic fields in the device we implement numerically the conventional twin-wire method. A good agreement with experimental measurements is observed, showing a promising way to determine coupling impedances of components of particle accelerators before construction.

 
 
WEA3MP01 Strong-Strong Beam-Beam Simulations beam-beam-effects, simulation, damping, collider 250
 
  • T. Pieloni
    CERN, Geneva
  During the collision of two charged beams the strong non-linear electromagnetic fields of the two beams perturb each other. This effect is called beam-beam interaction. Of particular interest in present and future machines are studies of the behaviour of equally strong and intense beams, the so-called strong-strong beam-beam interaction. After a careful definition of strong-strong beam-beam effects, I describe the applications where such studies are required. A major issue for strong-strong simulations are the computational challenges which are discussed. Finally I shall describe some of the modern techniques and procedures to solve them.  
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WEA4IS02 Numerical Computation of Kicker Impedances: Towards a Complete Database for the GSI SIS100/300 Kickers kicker, impedance, simulation, extraction 277
 
  • B. Doliwa, T. Weiland
    TEMF, Darmstadt
  Funding: Work supported by the GSI and the DFG under contract GK 410/3.

Fast kicker modules represent a potential source of beam instabilities in the planned Facility for Antiproton and Ion Research (FAIR) at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. Containing approximately six tons of lossy ferrite material, the more than forty kicker modules to be installed in the SIS-100 and SIS-300 synchrotrons are expected to have a considerable parasitic influence on the high-current beam dynamics. In order to be able to take these effects into account in the kicker design, a dedicated electromagnetic field software for the calculation of coupling impedances has been developed. Here we present our numerical results on the longitudinal and transverse kicker coupling impedances for the planned components and point out ways of optimization. Besides the inductive coupling of the beam to the external network -relevant below 100 MHz- particular attention is paid to the impact of ferrite losses up to the beam-pipe cutoff frequency.

 
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WEA4IS03 2-D Electromagnetic Model of Fast-Ramping Superconducting Magnets simulation, dipole, induction, shielding 283
 
  • B. Auchmann, S. Russenschuck, R. de Maria
    CERN, Geneva
  • S. Kurz
    Robert Bosch GmbH, Frankfurt
  The simulation of pulsed superconducting magnets has gained importance at the verge of fast-ramping cyclotron projects. The ROXIE program has been devised for the design and optimization of superconducting magnets. The 2-D electromagnetic model of a fast-ramping magnet in ROXIE consists of
  1. a representation of strands by line currents,
  2. a coupling of the finite element method and the boundary element method to take into account the field contribution of the magnet yoke, as well as eddy-current effects in conductive bulk material,
  3. a model for persistent currents,
  4. a model for inter-filament coupling currents, and
  5. a model for inter-strand coupling currents in Rutherford-type cables.
We will present the coupling of all these effects in the mathematical framework of the theory of discrete electromagnetism. We will then proceed to demonstrate how the coupled approach helps to understand a pulsed magnet's behavior. Each of the above effects leaves an identifiable signature in the measured field quality and contributes to the losses. With ROXIE, we can trace measurements to their origin and make predictions based on experience and simulation. 		 
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