The effect of transmission lines and switching action on the electrical signals in a powerful capacitive discharge

A numerical model for the equivalent electrical circuit of a capacitive discharge that includes the effects of finite closure time of switches and finite transit time in the transmission line is presented. An approximate analytical method to predict the oscillations that can be excited in the circuit is developed. The model yields complex behavior over time of the magnitudes of currents and voltages in pulsed circuits in the simple circuit configurations studies. Some of the oscillations predicted by the calculations admit simple physical interpretations in limiting cases (and are then predictable without the need of complex calculations); however, the rest of the observed features are not amenable to easy interpretation. The numerical solutions of the model are compared with experimental signals measured in a plasma focus device. Good agreement with many of the observed features is noted. The model can be extended easily to other types of circuits (Marx generators, Blumlein lines, etc.)