Fast rising, slow decaying magnetic field generator for special applications in UK industry

This paper describes a prototype version of a novel magnetic field generator for use in a number of special applications in UK industry. Proof of principle considerations were directed towards a single-shot device that was required to establish a magnetic field that rises very quickly but subsequently decays very slowly. The prototype system uses a fast capacitor bank as a power supply and a low-resistance cryogenically cooled inductor as an energy storage element. When the capacitor is discharged it feeds current to a load coil, and when this reaches its maximum value the coil and inductor are simultaneously crowbarred by a very low-resistance switch based on explosive technology. Experimental results are presented to show that the prototype system produces a 50 kA current and a 2 T magnetic field, rising to their maxima with about a 7.5 /spl mu/s time constant before decaying with about a 1.5 ms time constant. Comparisons between experimental results and theoretical predictions enable important conclusions to be drawn concerning the dynamic resistive properties of the various components of the system.