Repetitive operation of water-filled Blumlein generator

A water-filled Blumlein generator was operated at different repetition rates of up to 15 Hz, and its temporal performance was investigated. The Blumlein generator having an impedance of 10 Omega provides a rectangular voltage pulse with an amplitude of 200 kV and a duration of 75 ns into a matched load. The resistance of the water in the line decreases quickly at > 10 Hz during a continuous operation for an hour and results in a decrease in the output voltage of the Blumlein line. The generator works with a repetition rate of up to 6 Hz without serious degradation in the voltage, while the averaged power density dissipated in the water is approximately 40 mW/cm(3). The increase in the water temperature during operation is only a few degrees. This implies that the resistive heating of the water is not the dominant cause of the decrease in the water resistance. (C) 2001 American Institute of Physics.