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

Summary form only given, as follows. Describes a prototype version of a novel concept for use in a magnetic field generator required for a number of special applications in UK industry. Initial proof of principal considerations were directed towards a single-shot device, which was required to establish a magnetic field that rose very quickly but which then decayed very slowly. The prototype system comprises a fast capacitor bank as a power supply and a low-resistance cryogenically cooled ballast inductor as an inductive energy storage element. When the capacitor is discharged it feeds current to a load coil, and when the current reaches its maximum value the coil and inductor are crowbarred simultaneously by means of a very low resistance crowbar switch based on explosive technology. Proof of principle experimental results are presented to show that the prototype system produces a 100 kA current (and also a 2 T magnetic field) rising to its maximum with a time constant of about 7.5 microseconds, but subsequently decaying with a time constant of more than 2 ms. A comparison between corresponding experimental results and computer based theoretical predictions enables important conclusions to be drawn concerning the dynamic resistive properties of the various components of the system. A repetitive design is presently under consideration.