The effect of transmission lines and switching action on the electrical signals in plasma focus devices

Summary Form only given, as follows. A model for the electrical circuit of plasma focus devices that includes a finite transit time in the transmission line and finite closure times of the spark gap and breakdown in the gun has been developed. The evolution of the inductance of the gun is calculated with a simple snow-plow model. The voltage between the electrodes, V(t), and the time derivative of the current, dI/dt, have been calculated with this model for different values of the relevant parameters. The results have shown that the frequencies of the oscillations present in V(t) and dI/dT can be derived from a simple equivalent circuit in which the transmission line is replaced by an appropriate frequency-dependent impedance. The predicted values of V(t) and dI/dt corresponding to the parameters of the authors´ plasma focus device showed good agreement with the measured ones, indicating that the high-frequency oscillations found in the signals at the beginning and at the focus stage of the discharge are mainly due to the transmission line.<>