Abstract
Boundary-Induced Coupling Currents (BICCs) are generated in multistrand superconducting cables during a field sweep if a) the field sweep and/or b) the electrical contacts between the strands of the cable vary along the cable. Typical parts in a coil which cause large BICCs are the connections between two cables in or outside a coil and the coil ends of racetrack magnets.
In the first part of the paper several approaches for describing and calculating BICCs are reviewed. Attention is paid on the steady-state as well as the time dependent solutions.
In the second part of the paper the consequences of BICCs on the behaviour of magnets are discussed. These are additional field variations along the magnet length, additional coupling losses and a non-uniform distribution of coupling losses and current among the strands, resulting in a reduced stability. Several effects are illustrated by means of measurements on model dipole magnets. It is shown how the additive effect of all the BICCs in a coil is rather unpredictable so that similar coils can have rather different BICC related behaviour.
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References
G. Ries and S. Takâcs, “Coupling losses in finite length of superconducting cables and in long cables partially in magnetic field”, IEEE Trans. on Magn. MAG-17, pp. 2281–2284 (1981).
S. Takâcs, “Coupling losses in cables in spatially changing ac fields”, Cryogenics 22, p. 661 (1982).
S. Takâcs, “AC losses and time constants of flat superconducting cables in inhomogeneous magnetic fields”, SC Sci. Techn. 9, pp. 1–4 (1996).
Krempasky, C. Schmidt, “Influence of a longitudinal variation of dB/dt on the magnetic field distribution of accelerator magnets”, Appl. Phys. Lett. 66 (12), pp. 1545–1547 (1995).
Krempasky, C. Schmidt, “Theory of supercurrents and their influence on field quality and stability of superconducting magnets”, J. Appl. Phys. 78 (9), pp. 5800–5810 (1995).
Krempasky, C. Schmidt, “A possible explanation of the problem of ramp-rate limitation in large superconducting magnets”, IEEE Trans. Magn. 32 (4), pp. 2340–2344 (1996).
A.A. Akhmetov, A. Devred, and R. Schermer, “Current loop decay in Rutherford-type cables”, SSCL preprint 485 (1993).
A.P. Verweij, “Current redistribution in the cables of LHC magnets”, CERN LHC project note 90 (1997).
S.A. Egorov, “AC coupling losses in superconducting cables of finite length”, ITER–RF–MS/A CL–02–09–94 (1994).
A.A. Akhmetov and T. Ogitsu, “Periodicity of eddy currents in flat Rutherford-type cables”, SSC internal note MD-TA-245 (1993).
A.A. Akhmetov, K. Kuroda and M. Takeo, “Influence of sample geometry on amplitude of eddy current oscillation in Rutherford-type cables”, IEEE Trans. Appl. SC 5 (2), pp. 725–728 (1995).
G.H. Morgan, “Eddy currents in flat metalf-illed superconducting braids”, J. Appl. Phys. 44, pp. 3319–3322 (1973).
A.A. Akhmetov, A. Devred, and T. Ogitsu, “Periodicity of crossover currents in a Rutherford-type cable subjected to a time-dependent magnetic field”, J. Appl. Phys. 75 (6), pp. 3176–3183 (1994).
A.A. Akhmetov, K. Kuroda, K. Ono and M. Takeo, “Eddy currents in flat two-layer superconducting cables”, Cryogenics 35, pp. 495–504 (1995).
A.P. Verweij, and H.H.J. ten Kate, “Coupling Currents in Rutherford cables under time varying conditions”, IEEE Trans. On Appl. SC 3, pp. 146 (1993).
A.P. Verweij, and H.H.J. ten Kate, “Super Coupling Currents in Rutherford type of cables due to longitudinal non-homogeneities of dB/dt”, IEEE Trans. On Appl. SC 4, pp. 404–407 (1995).
A.P. Verweij, Electrodynamics of Superconducting Cables in Accelerator Magnets, PhD thesis University of Twente, The Netherlands (1995).
A.P. Verweij, “Modelling Boundary-Induced Coupling Currents in Rutherford-type cables”, IEEE Trans. Appl. SC 7, pp. 723–726 (1997).
A.P. Verweij, M.P. Oomen, and H.H.J. ten Kate, “Boundary-Induced Coupling Currents in a 1.3 m Rutherford-type cable due to a locally applied field change”, IEEE Trans. Appl. SC 7, p. 270 (1997).
W.B. Sampson and A.K. Ghosh, “Induced axial oscillations in superconducting dipole windings”, IEEE Trans. Appl. SC5, pp. 1036–1039 (1995).
A.A. Akhmetov, K. Kuroda, T. Koga, K. Ono and M. Takeo, “Decay of long current loops in the superconducting cables”, Proc. 2“d EUCAS 1, Edinburgh, UK, pp. 527–530 (1995).
E.A. Badea, “Numerical calculation of the magnetic field produced by currents circulating through two opposite strands of a Rutherford-type cable”, SSC internal note MD-TA-262 (1993).
H. Bruck et al., “Observation of a periodic pattern in the persistent-current fields of the superconducting HERA dipole magnets”, DESY 91–01 (1991) or Proc. ‘81 IEEE Part. Acc. Conf., pp. 2149–2151 (1991).
A.K. Ghosh, K.E. Robins, and W.B. Sampson, “The ramp rate dependence of the sextupole field in superconducting dipoles”, IEEE Trans. on Magn. 30, pp. 1718–1721 (1994).
L. Bottura, Z. Ang, and L. Walckiers, “Experimental evidence of Boundary-Induced Coupling Currents in LHC prototypes”, IEEE Trans. Appl. SC 7, pp. 801–804 (1997).
L. Bottura, L. Walckiers and R. Wolf, “Field errors decay and ”snap-back“ in LHC model dipoles”, IEEE Trans. Appl. SC 7, pp. 602–605 (1997).
R.I. Schermer, “Status of superconducting magnets for the Superconducting Super Collider”, IEEE Trans. Magn. 30, pp. 1587–1594 (1994).
V.S. Vysotsky et. al., “New method of current distribution studies for ramp rate stability of multistrand superconducting cables”, IEEE Trans. Appl. SC 5, pp. 580–583 (1995).
M. Takayasu et al., “Spike voltages seen during quick charge ramp limitation tests on Nb3Sn cable-inconduit conductors”, IEEE Trans. Appl. SC 7, pp. 150–154 (1997).
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Verweij, A.P. (1998). Review on Boundary-Induced Coupling Currents. In: Balachandran, U.B., Gubser, D.G., Hartwig, K.T., Reed, R.P., Warnes, W.H., Bardos, V.A. (eds) Advances in Cryogenic Engineering Materials . Advances in Cryogenic Engineering, vol 44. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-9056-6_139
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