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Current density distribution in multiple YBCO coated conductors by coupled integral equations

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Current density distribution in multiple YBCO coated conductors by coupled integral equations

coupled integral equations Luciano Martini*, Roberto Brambilla*, Francesco Grilli**, Frédéric Sirois**, D. N. Nguyen*** ASC 2008 Applied Superconductivity Conference Chicago, Illinois USA, 17-22 Agosto 2008 Ieee Transactions on applied Superconductivity, Vol. 19, N. 3, June 2009 * CESI RICERCA ** ECOLE POLYTECHNIQUE DE MONTREAL, MONTREAL, QC, CANADA ***S. P. ASHWORTH, LOS ALAMOS NATIONAL LABORATORY, LOS ALAMOS, NM, USA In this paper we present a new model to compute the current density distribution and the ac losses in multiple YBCO coated conductors by means of coupled integral equations implemented in a finite- element (FE) environment. The model considers the superconducting tapes as 1-D objects and allows overcoming the problem of the mesh of conductors of very large aspect ratio, typical of 2-D implementations; as a result, computing times are much shorter. The interaction between the different conductors is taken into account by means of a coupling of the electromagnetic variables. The magnetic field distribution in the space between the conductors is calculated by coupling the 1-D model with a standard 2-D magneto-static model, which uses the computed current density distributions as sources for the field. The model also allows for the presence of magnetic substrate and metal coating in the coated conductors, which may strongly influence the current density and field distributions. Results are compared with those obtained with standard 2-D implementations, with analytical models and with experimental results.

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