Induced current effects in Faraday’s law and introduction to flux compression theories

The exact dynamical and electrical equations for a rod moving on conducting rails in a magnetic field are quite complicated and do not clearly reveal the nature of the physical processes involved, especially in regard to the electromechanical energy transfer taking place in the system. Considerable conceptual simplification is achieved by considering the two‐dimensional version of the rod and rails system. The dynamics and the energy balance of the entire system can be established without difficulty in the most general conditions. The complete solution of the problem is obtained in one particular case. More importantly, such a two‐dimensional model can provide a simplified but effective introduction to the field of flux compression theories, an active area of research concerned with the design and utilization of flux pumps and the generation of very intense or very weak magnetic fields. An idealized example is treated in detail. Finally, we use the simplified model to briefly discuss other new techniques and devices based on Faraday’s induction law. Among these, the electromagnetic forming of metal sheets which uses the magnetic pressure of an expanding magnetic field to swage them into a desired shape has received a number of industrial applications. Another, more speculative field of interest concerns railguns and other electromagnetic launchers, which are still in the experimental stage, but may someday surpass the traditional chemical explosives or provide a more economical alternative to conventional rocket launching.