Mutual Inductance Between a Coil and an Electromagnetically Launched Plate

摘要

A possible countermunition against kinetic energy (KE) rods is a thin squaremetal launched edge-on so that an edge strikes the rod first followed by the rest of the plate. A properly designed coil gun can launch plates edge-on to velocities of several hundred meters per second. The proper design of the coil gun depends on knowing the mutual inductance between the coil and the plate, which was calculated by assuming that the current distribution in plate can be described by a polynomial that has some arbitrary coefficients. These coefficients were determined by equating the magnetic induction of the current distribution to the negative of the applied magnetic induction of the launch coil at selected points on the plate. This step was aided by the fact that all the integrals arising from the Biot-Savart law are analytic. In the next step, the mutual inductance was calculated from the current distribution and the applied magnetic induction. The calculation was repeated for various plate positions in the coil. These results were used to design the power supply for the launch coil and to calculate the final velocity of the plate.