Equivalent circuits and parameters for induction-type electromagnetic launchers

The authors present a lumped parameter equivalent circuit model for cylindrical, induction-type, electromagnetic coil-launchers based on an electromagnetic field transmission-line approach. Basic closed-form formulas for performance analysis are derived from the model. System parameters and performance indices are obtained from the circuit model and related to the dimensions of the launcher. Currents in the linear array of barrel and projectile (sleeve) conductors are represented by two voltage-controlled current sources. If the barrel and sleeve are approximated by two equivalent cylindrical current sheets, then the circuit model becomes simplified, the Bessel function arguments become real, and the barrel may be modeled by a single constant voltage source. A modified planar model is also considered. Formulas for determining the electrical time constants of the launcher are included. Data from experiments with a small model are compared with calculated results