A TOOL FOR FORCE MODEL ANALYSIS FOR PLASMA ARMATURE RAILGUNS

The exact forces and the way they act to accelerate and retard a projectile in a railgun and the correct model to represent the data have been debated for years. This paper demonstrates the use of a well known method (Chapman-Kirk) for identification of force parameters in a relatively simple nonlinear differential equation model of railgun projectile motion. Where other methods of parameter identification failed, this method converged well. The data used to demonstrate the procedure is a limited set of CHECMATE data (three shots at approximately the same conditions) and one shot from another gun. The input data to the procedure is the measured current and B time position data. Although the analysis of the results do not show that the model is adequate and correct over a wide range of operative conditions, the force parameters obtained are reasonable and some are substantiated by other methods.