Experimental simulation of pulsed field losses in tokamak toroidal field coils

Experiments have been carried out to measure loss in a twisted multifilamentary composite superconductor when exposed to a transient longitudinal field. We investigate the variation of losses both as a function of transverse applied field and of sample transport current. Losses are probed mainly by measurement of the dynamic resistivity of the sample during the longitudinal pulse. Experimental results are compared with theories 1,2,5,6,8 for the zero transport current case. The extension of theory to include transport current is also discussed, and the impact on tokamak toroidal field coil design is considered.