Development of an explosive driven 2 MJ helical generator

Explosively-driven flux compression generators are used in a variety of high-current and high-energy applications, to convert the chemical energy stored in an explosive charge into electromagnetic energy. To assist with the design of these devices, a simple but very efficient 0-dimensional code for multi-stage devices was developed and validated, using published data. Together with other tools, such as a simple mode for the mechanical stress in the coils, the code provided the basis for the design and manufacture of an 8-stage generator (FLEXY). Experiments have confirmed that this is capable of generating 2 MJ of electromagnetic energy, and of delivering most of this to a metallic exploding-foil fuse. The good reproducibility of experimental results, even in the rate-of-change of current, provides a reliable enhancement of the 100 kJ capacitor bank used as the priming source. Two-dimensional modelling is being studied for the development of both high-energy generators and small-scale autonomous inductively-coupled systems. Conceptually, the helical coil, transformed into a number of rings of the mirrored θ-distribution of the armature currents, is considered as a number of independent theta-currents. This provides a detailed description of the generator performance, and appears to be the only way of describing the dynamic transformer used in inductively-coupled systems