A more general model for determination of plasma armature current distribution from B-dot voltage by method of least squares

A more general and precise model for the B-dot coil voltage induced by the railgun plasma armature current has been derived and used to obtain armature current distributions. Previously, the voltage model assumed the current elements in the armature were no closer than a bore diameter from the coil. A solution for the coil voltage has been found which eliminates this approximation. In addition, the model has been generalized to include multiple armature currents in any direction perpendicular to the rails, and nonuniform current across the bore. The model is used with least squares reduction, as in previous work. Using this model, current distributions were determined for the square-bore and the MARC IV (four perpendicular armatures) railguns. The results of these reductions are presented.< >