Current-voltage characteristics of a high-current pulsed discharge in air

The time-dependent arc voltage and resistance of a high-current pulsed discharge in air are obtained accurately by solving the circuit equation using the measured values of the current and breakdown voltage. Unipolar critically damped or overdamped pulsed discharges, with rise times of about 0.7 μ and peak currents in excess of 20 kA, are investigated. These discharges are characterized by four phases: initial phase, quasistationary phase, transient phase, and relaxation phase. The quasistationary phase occurs between the time of the current maximum and twice this time. The transient phase, which occurs after the quasistationary phase, corresponds to a negative slope of the V-I characteristic. The variable parameters were electrode separation, and gas pressure. The minimum arc resistance, at peak current, was about 50 mΩ