Scaling of the E(J) Characteristics in the ITER Type Nb3Sn Strands in Relation to the Applied Strain and Magnetic Field

Voltage- current characteristics VCC(epsiv, B, 4.2 K) have been measured in the range of the applied axial tensile strain (epsiv) from 0% to 0.93% at magnetic fields 10 T and 12 T for ITER type bronze processed Nb₃Sn strand and for similar strand with enhanced mechanical strength in which part of stabilizing copper was replaced by high strength high conductivity microcomposite Cu-Nb material. The results of description of the electric field-current density characteristics E(J,epsiv,B,4.2 K) are presented. To describe experimental database E( J) versus strain and magnetic field the relation is used containing four fitting parameters. Three parameters,namely: C, T_c(0) and B_c2(0, epsiv) describe. Additional parameter characterizes the smoothness of E( J). Good agreement of experiment and calculation has been obtained.