Influence of Conductor Geometry on Normal-Zone Propagation Velocities in NbTi/CuNi Composite Super-Conductors
In superconducting wires with a CuNi matrix for A.C. use, normal transition is easily induced by various disturbances because the CuNi matrix has high electrical resistivity and very low thermal conductivity. Therefore, the thermal and the electromagnetic behaviors of NbTi/CuNi composite conductor during quench are apparently different from those of conventional copper-stabilized composites. We have investigated normal-zone propagation velocities in applying D.C. transport current in NbTi/Cu10%Ni superconductors taking the effect of three-dimensional temperature gradient at normal front into account in the previous paper1. To investigate the influence of conductor geometry on normal-zone propagation velocities in NbTi/CuNi composite superconductors, we prepared several kinds of sample wires. In these wires we measured normal-zone propagation velocities in applying both D.C. and A.C. transport current, and compared them with analytical result by the three dimensional finite element method(3D-FEM), taking the redistribution of currents into account; the influence of the transverse electrical conductance on the current sharing at normal front in a composite. From their comparisons, the influence of the structure of wire cross-section on normal-zone propagation velocities is discussed.
KeywordsPropagation Velocity Transport Current High Electrical Resistivity Sample Wire Composite Wire
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- 2.H.H.J. ten Kate, H. Boschman and L.J.M. van de Klundert, “Normal Zone Propagation Velocities in Superconducting Wires having a High-resistivity Matrix,” Advanced in Cryogenic Engineering 34: 1049 (1988).Google Scholar