Magnetic flux-compression driven by exploding single-turn coils

A novel hybrid approach to producing ultrahigh magnetic fields has been successfully demonstrated using a 20 kJ capacitor bank. The explosion of a single-turn copper coil at peak field is used to generate shock-waves, which in turn produce in the aluminum powder filling the single-turn coil a circular insulator-metallic transition advancing towards the coil centre and performing magnetic flux-compression. The flux compression almost precisely doubles the initial flux density generated by the coil, so that some of the Joule energy deposited in the coil is re-use during the process as kinetic energy, rather than being lost as in a standard single-turn experiment. Attempts to scale up the basic arrangement to 80 kJ were only partially successful, but it was nevertheless possible to significantly prolong the duration of the megagauss field that was produced. It is believed that a hybrid method using small explosive charges to produce the shock-waves necessary for flux-compression can certainly be used when attempting to produce record magnetic flux densities in indoor experiments, without the need for a large and costly MJ size capacitor bank.